Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 362 journals)
    - CERAMICS, GLASS AND POTTERY (31 journals)
    - MACHINERY (34 journals)
    - MANUFACTURING AND TECHNOLOGY (223 journals)
    - METROLOGY AND STANDARDIZATION (5 journals)
    - PACKAGING (19 journals)
    - PAINTS AND PROTECTIVE COATINGS (4 journals)
    - PLASTICS (42 journals)
    - RUBBER (4 journals)

PLASTICS (42 journals)

Showing 1 - 32 of 32 Journals sorted alphabetically
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 9)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advanced Industrial and Engineering Polymer Research     Open Access   (Followers: 4)
Advances in Polymer Technology     Open Access   (Followers: 13)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 9)
Cirugia Plastica Ibero-Latinoamericana     Open Access  
European Polymer Journal     Hybrid Journal   (Followers: 44)
International Journal of Biobased Plastics     Open Access   (Followers: 2)
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 6)
International Polymer Processing     Full-text available via subscription   (Followers: 1)
Iranian Journal of Polymer Science and Technology     Open Access   (Followers: 1)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 115)
Journal of Inorganic and Organometallic Polymers and Materials     Hybrid Journal   (Followers: 8)
Journal of Polymer Research     Hybrid Journal   (Followers: 7)
Journal of Polymer Science Part C : Polymer Letters     Hybrid Journal   (Followers: 5)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Majalah Kulit, Karet, dan Plastik     Open Access  
Microplastics and Nanoplastics     Open Access  
Plastic and Polymer Technology     Open Access   (Followers: 40)
Plastic and Reconstructive Surgery     Hybrid Journal   (Followers: 30)
Plastics Engineering     Partially Free  
Polymer     Hybrid Journal   (Followers: 86)
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Engineering & Science     Hybrid Journal   (Followers: 15)
Polymer Science Series B     Hybrid Journal   (Followers: 4)
Polymer Science Series C     Hybrid Journal   (Followers: 3)
Polymer Science Series D     Hybrid Journal   (Followers: 3)
Polymer Science, Series A     Hybrid Journal   (Followers: 3)
Polymer-Plastics Technology and Materials     Hybrid Journal   (Followers: 5)
Reinforced Plastics     Full-text available via subscription   (Followers: 17)
SPE Polymers     Open Access  
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Polymers and Polymer Composites
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0967-3911 - ISSN (Online) 1478-2391
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  • Colloidal characteristics of gelatin-treated clay: Intercalation,
           stability, wettability, and rheological properties

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      Authors: Xuwu Luo, Guancheng Jiang, Xinliang Li, Lili Yang
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1361-S1370, November 2021.
      In this paper, sodium montmorillonite was modified with gelatin of different concentrations, and various colloidal characteristics of the gelatin-treated clays were measured and analyzed in detail. First, the influence of gelatin on the interlayer space of Mt layers was investigated by X-ray diffraction analysis. Moreover, the aggregation of Mt particles was examined using a combination of electron microscopy and particle size distribution experiments, while the variation of the electrical property of Mt was measured using ζ potential test. Gelatin of different concentrations can increase the particle size of Mt in different degrees. The addition of 4% gelatin could improve the ζ potential of Mt from −30.65 to −15.55 mV. The wettability change of modified Mt induced by the adsorption of gelatin was followed by measurements of water contact angle and observations of the morphology of Mt/gelatin membrane through SEM images. 4% gelatin could improve the water contact angle of Mt to 81.3°. Finally, the rheological properties of Mt/gelatin dispersion including shear viscosity and shear stress were measured using a stress-controlled rheometer. All of the results were consistent by showing that the overall colloidal characteristics and behavior of the gelatin-treated Mt strongly varied depending on the gelatin concentration used in the modification process. These results can provide a deep and comprehensive understanding of the colloidal properties of clay/gelatin systems and give important guidance for the performance design and improvement of Mt/gelatin composite materials. Furthermore, this study can also be expanded the application of gelatin and its composites to other fields.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:22:08Z
      DOI: 10.1177/09673911211049111
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Production of bacterial cellulose biopolymers in media containing rice and
           corn hydrolysate as carbon sources

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      Authors: Karina C de Souza, Gabriela R dos Santos, Felipe CS Trindade, Andréa Fernanda de S Costa, Yeda MB de Almeida, Leonie A Sarubbo, Glória M Vinhas
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1466-S1474, November 2021.
      Bacterial cellulose (BC) is a promising option for ecologically viable processes. In this work, BC was produced using starch hydrolysate (rice and corn flakes) as carbon sources. The starch was hydrolyzed by fungus for glucose production. A maximum yield of 2.80 ± 0.43 g/L of BC was obtained with the hydrolyzed rice medium. Moreover, BC produced in the rice and corn media had crystallinity of around 50%. Fourier-transform infrared spectrometry confirmed the functional groups in BC as well as the absence of contaminants from production process. The thermogravimetric analysis revealed that the polymers formed with alternative media had greater thermal stability. Scanning electron microscopy revealed a morphological structure with the random arrangement of nanofibrils in a non-uniform manner distributed in the weave of both polymeric films. The biofilms produced in different media had similar properties to those of films obtained with a conventional medium, revealing that the polymeric characteristics are not modified.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:21:11Z
      DOI: 10.1177/09673911211059706
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Vibroacoustic design optimization of curved composite shells

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      Authors: Rilwan K Apalowo, Dimitrios Chronopoulos
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1520-S1531, November 2021.
      The need to simultaneously optimize the structural design properties, and attain a satisfactory vibroacoustic performance for composite structures, has been a challenging task for modern structural engineers. This work is aimed at developing a statistical energy analysis (SEA) based numerical scheme for computing the optimal design parameters of each individual layer of layered curved shells having arbitrary complexities and layering. The main novelty of the work focuses on the computation of SEA properties for curved composite shells and derive the sensitivities of the acoustic transmission coefficient, expressed through the computed SEA properties, with respect to the structural design characteristics to be optimized. A wave finite element approach is employed to calculate the wave propagation constants of the curved shell. The calculated wave constants are then applied to compute the vibroacoustic properties for the curved shell using a SEA approach. Sensitivity analyses are conducted on the vibroacoustic properties to estimate their response to changes in the structural properties. Gradient vector is then formulated and hence the Hessian matrix, which is employed to formulate a Newton-like optimisation algorithm for optimizing the properties of the layered composite shell. The developed scheme is applied to a sandwich shell; optimal design parameters of [math] and [math] are obtained for the facesheet and the core of the shell whose base parameters are [math] and [math], respectively. This simultaneously optimizes the structure with maximum stiffness and minimum mass and attains a satisfactory dynamic performance for acoustic transmission through the sandwich shell. The principal advantage of the scheme is the ability to accurately model composite panels of arbitrary curvature at a rational computational time.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:19:16Z
      DOI: 10.1177/09673911211060654
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Physico-mechanical properties of polylactic acid bio-nanocomposites filled
           by hybrid nanoparticles

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      Authors: Seyed Mehdi Mirabolghasemi, Mohsen Najafi, Alireza Azizi, Mehdi Haji Bagherian
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1510-S1519, November 2021.
      This study is aimed to investigate the effect of the simultaneous incorporation of cellulose nanocrystals (CNC) and silver nanoparticles (SN) on the mechanical, biodegradability, and water vapor permeability of polylactic acid (PLA)-based films. PLA films and their nanocomposites containing different levels of CNC (0.333, 1 and 1.667 phr) and SN (0.333 phr) were prepared by solution casting method. CNC was reacted with acetic anhydride to improve its compatibility and miscibility with PLA. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), tensile test, and water vapor permeability and antibacterial tests were employed to characterize the samples. The biodegradability was assessed by measuring the weight loss upon burial in the soil. FTIR spectroscopy confirmed the modification of cellulose nanocrystals. TGA test showed that partial acetylation slightly improved the thermal stability of CNC. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the nanocomposite relative to pure polylactic acid. The biodegradability and water vapor permeability of the samples decreased upon CNC incorporation. The antibacterial properties of the films showed the higher resistance of the gram-positive bacteria as their cell walls include a peptidoglycan layer.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:16:15Z
      DOI: 10.1177/09673911211060132
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Formulation, optimization, and characterization of amlodipine besylate
           loaded polymeric nanoparticles

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      Authors: Vibha Chourasiya, Sarvesh Bohrey, Archna Pandey
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1555-S1568, November 2021.
      The objectives of this work were to formulate and optimize amlodipine besylate loaded polymeric nanoparticles by using factorial design. The emulsion solvent evaporation method was employed successfully to produce the drug loaded polymeric nanoparticles and the optimization was done by the help of the 24 factorial design. The effect of the main preparation variables on the dependent variables such as nanoparticle size and % drug entrapment efficiency was studied for the optimization of the nanoparticles. The characterization of these nanoparticles was done by the different parameters such as interaction between the excipients, size, morphology, zeta potential, % drug entrapment efficiency, % process yield, and in-vitro drug release behavior. FTIR, DLS, TEM, AFM, zeta potential studies, and dialysis bag method were performed for this purpose. The in vitro drug release data were analyzed by different kinetic models to know the release mechanism. The optimized nanoparticles were spherical in shape and showed particle size 91.5 ± 4.3 nm, PDI 0.368 ± 0.014, zeta potential −17.5 mV, % drug entrapment efficiency 74.06 ± 2.1%, and % process yield 78.51 ± 1.8%. The release kinetics studies revealed that drug release from the nanoparticles follow the Korsmeyer–Peppas model.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:16:15Z
      DOI: 10.1177/09673911211056154
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Thermal behaviour of benzoxazine blends based on epoxy and cyanate ester

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      Authors: Balaji Krishnasamy, Hariharan Arumugam, Mohamed Iqbal M, Alagar Muthukaruppan
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1475-S1485, November 2021.
      In the present work, an attempt has been made to develop high-performance polymeric hybrid binary blends of epoxy/benzoxazine and benzoxazine/cyanate ester with varying weight percentages (25/75, 50/50 and 75/25 wt%) of resins, namely, bisphenol-F epoxy resin (DGEBF), benzoxazines [bisphenol–F/aniline (BF-a) and imidazole core-based bisphenol/aniline (IBP-a)] and cyanate ester [bisphenol-F bifunctional cyanate ester (BF-CE)]. The molecular structure, polymerisation temperature/cure behaviour, glass transition temperature (Tg) and thermal stability of the neat polymeric matrices and binary hybrid blends of polymeric matrices were characterised using different analytical techniques, viz. Fourier Transform infra-red spectroscopy (FTIR), Nuclear Magnetic Resonance spectroscopy (NMR), Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA). Among the binary hybrid blends, the lowest polymerisation temperatures (Tp) were noticed in the case of blends of epoxy/benzoxazine were 219°C for DGEBF/BF-a (25/75 wt%) and 170°C for DGEBF/IBP-a (25/75 wt%). Similarly, in the case of blends of benzoxazine/cyanate ester, the lowest values of Tp observed were 155°C and 153°C for BF-a/BF-CE (75/25 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. The highest values of Tg observed for the blends of epoxy/benzoxazine were 175°C and 254°C for DGEBF/BF-a (25/75 wt%) and DGEBF/IBP-a (25/75 wt%), respectively. Whereas, the highest values of Tg observed in the case of blends of benzoxazine/cyanate ester were 234°C and 278°C for BF-a/BF-CE (25/75 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. From the TGA results of blends, the maximum degradation temperature (Tmax) and limiting oxygen index (LOI) value calculated from the char yield, which ascertain that almost all the binary hybrid blends of epoxy/benzoxazine and benzoxazine/cyanate ester possess good flame retardant behaviour.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:11:52Z
      DOI: 10.1177/09673911211059714
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Influence of the printing parameters on the properties of Poly(lactic
           acid) scaffolds obtained by fused deposition modeling 3D printing

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      Authors: Abraão CD Nascimento, Raquel CDAG Mota, Livia RD Menezes, Emerson OD Silva
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1052-S1062, November 2021.
      3D printing techniques are of great interest in the sector of scaffold development aiming for bone tissue regeneration mainly due to the possibility of customizing the scaffold according to the area of the bone defect to be regenerated. Among the 3D printing techniques, the fused deposition modeling (FDM) stands out as promising because it does not require the use of solvents and toxic components throughout the manufacturing process of the scaffold. In this sense, the present article aims to evaluate the influence of the printing speed and the temperature of the printing head on the properties of poly(lactic acid) scaffolds. Three speeds of the printing head (4600 mm/min, 480 mm/min, and 500 mm/min) and two different extrusion temperatures (200oC and 220oC) were evaluated, maintaining the architecture and all other printing conditions constant. After obtaining the scaffolds, they were characterized by the following techniques: Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), time-domain nuclear magnetic resonance (TD-NMR), compressive modulus, L929 cell viability, and enzymatic degradation. The results obtained showed that the increase in printing temperature and speed was able to influence some properties of the material: increase crystallinity, compressive modulus, thermal resistance, and reduce molecular mobility and enzymatic degradation rate of the scaffolds. These findings are promising and indicate that, by altering only the basic parameters of 3D printing, it is possible to modulate the properties of the scaffolds obtained, to achieve greater crystallinity and a superior compressive modulus.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:11:51Z
      DOI: 10.1177/09673911211040770
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Improvement of technological properties of wood plastic composites
           reinforced with glass and carbon fibre fabric

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      Authors: Sefa Durmaz, Yusuf Z Erdil, Erkan Avci
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1457-S1465, November 2021.
      In this study, HDPE-based flat-pressed WPCs were reinforced with glass fibre and carbon fibre woven fabrics, which could be used where high strength and stiffness are required. The effect of reinforcement on some physical, mechanical, and thermal properties and fire performance was investigated. According to the results, the increase in woven fabric density resulted in holding much water in the microvoids in the fabric, which increased water absorption up to 32.96%. Reinforcement also resulted in increased hardness. In general, continuous filaments in the fabric significantly increased mechanical properties. The improvement exceeded over 400% for tensile strength compared to unreinforced control samples, while the increases were 129% and 115% for the flexural strength and MOE, respectively. The interlocking of matrix and woven fabrics is an important factor that affects load transfer. The strong interaction between wood-polymer and the wood-polymer-woven fabric was observed from the SEM investigation. The thermal stability of composites was also improved, possibly due to the homogeneous distribution of heat within fibres. Glass and carbon fibres presumably acted as a buffer against increasing heat, increasing the onset temperature. Moreover, according to the LOI test, the need for oxygen increased from 24.72 to 26.01 with the effect of wood flour and reinforcement.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:08:49Z
      DOI: 10.1177/09673911211054266
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Copolymerization of palm oil with sulfur using inverse vulcanization to
           boost the palm oil industry

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      Authors: Amin Abbasi, Wan Zaireen Nisa Yahya, Mohamed Mahmoud Nasef, Muhammad Moniruzzaman, Ali Shaan Manzoor Ghumman
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1446-S1456, November 2021.
      Nowadays, most of the world’s palm oil is being produced in Malaysia and Indonesia; however, the demand for this vegetable oil as an edible oil is declining in many countries since consuming palm oil in excess can result in serious health problems. Consequently, finding new applications such as the production of bio-based polymers to make use of this cheap and abundant vegetable oil seems necessary. Herein, we report the copolymerization of palm oil with sulfur with different feed ratios via inverse vulcanization. The copolymers are then characterized using Fourier-transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction analysis. The results confirmed the formation of the polymers and their stability against depolymerization. Altogether, the obtained sulfur-palm oil copolymers showed great properties such as thermal stability up to 230°C under a nitrogen atmosphere and rubbery properties at room temperature. Although the Thermogravimetric analysis (TGA) thermograms had previously confirmed the high conversion of elemental sulfur into the polymeric structure by comparing the initial sulfur content and the final polysulfide content in the polymer, some unreacted elemental sulfur was also observed in the final product. Sulfur-palm oil (S-Palm oil) is a new green polymer that helps to find a new use for palm oil as a big industry as well as sulfur which is underutilized and left in stockpile as a byproduct in gas and petroleum refineries.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:07:28Z
      DOI: 10.1177/09673911211054269
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Synthesis and characterization of novel methacrylate copolymers having
           pendant piperonyl group: monomer reactivity ratio, thermal degradation
           kinetics, and biological activity

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      Authors: Ibrahim Erol, Bayram Gencer, Zeki Gurler
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1432-S1445, November 2021.
      In this study, 2-{[(2H-1,3-benzodioxol-5-yl)methyl]amino}-2-oxoethyl 2-methylprop-2-enoate (BMAOME) monomer was synthesized, and copolymers were prepared with glycidyl methacrylate (GMA). Structural characterizations of the compounds were performed using FTIR, 1H-, and 13C-NMR techniques. Monomer reactivity ratio values were calculated by Finemann–Ross (FR) and Kelen–Tudos (KT) methods. The Tg value of the polymers was determined by differential scanning calorimetry (DSC) and their thermal stability was determined by thermogravimetric analysis (TGA). The molecular weights (w and n) and polydispersity index of the polymers were determined by gel permeation chromatography. The Ea value of thermal decomposition was determined by using the Ozawa and Kissinger methods. The photo-stability of the copolymers was investigated. Furthermore, the photo-stability of the copolymers and the biological activity of polymers against different types of bacteria and fungi were investigated.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:06:34Z
      DOI: 10.1177/09673911211053978
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Viscoelastic and mechanical properties of CNT-reinforced polymer-based
           hybrid composite materials using hygrothermal creep

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      Authors: S Srikant Patnaik, Tarapada Roy
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1386-S1402, November 2021.
      In the present work, a combination of experimental and numerical procedure is proposed to study the effects of different hygrothermal conditions on the creep strain, viscoelastic properties of nanocomposites, and mechanical properties of such nanocomposite-based carbon fiber–reinforced polymer (CFRP) hybrid composite materials. Ultrasonic probe sonicator is used to randomly disperse the multiwalled carbon nanotubes into an epoxy to minimize agglomerations. Dynamic mechanical analysis is employed to conduct the creep tests under different hygrothermal conditions of such nanocomposite samples. The Findley power law is used to obtain the long-term creep behavior of nanocomposite materials. Prony series is used to determine the viscoelastic properties of nanocomposite material in the frequency domain. Coefficient of moisture expansion (CME) is independent of moisture concentration; thus, CME of the nanocomposite is also determined. Strength of materials and Saravanos–Chamis micromechanics (SCM) have also been utilized to obtain the mechanical properties of such hybrid composite materials under different hygrothermal conditions. It has been found that the inclusion of multiwalled carbon nanotubes in the nanocomposite and hybrid composites improves storage modulus and loss factor (i.e., tanδ) compared to the conventional CFRP-based composite materials under hygrothermal conditions.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T12:02:02Z
      DOI: 10.1177/09673911211052730
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Fabrication and optimization of PCL/PVP nanofibers with Lawsonia inermis
           for antibacterial wound dressings

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      Authors: Mehdi Varsei, Nadia Rahimi Tanha, Mohsen Gorji, Saeedeh Mazinani
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1403-S1413, November 2021.
      Anti-infection ability and desirable air permeability (AP) are the important aspects of wound dressings that should be regulated with regard to primary polymers and antibacterial agents. This study aims to fabricate and optimize a wound dressing with antibacterial properties. For this purpose, polycaprolactone (PCL) as a hydrophobic polymer and polyvinylpyrrolidone (PVP) as a hydrophilic polymer were electrospun with Lawsonia inermis (Henna) extract as an antibacterial component based on the experiments proposed by Design-Expert software. The morphology and properties of the wound dressing were studied by scanning electron microscopy, Fourier transform infrared, and AP. The response surface method (RSM) was used to determine the optimal fiber diameter and AP of the samples as a function of the polymer concentration and feed rate. The optimal PCL/PVL/Henna wound dressing has antibacterial properties against Gram-positive and Gram-negative bacteria while being biocompatible according to the MTT assay. These fibrous structures can be used as a wound dressing to prevent infection and accelerate wound healing; thanks to proper Henna release, breathability, swelling ratio, and mechanical performance.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T11:58:37Z
      DOI: 10.1177/09673911211053307
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Using potential of filament-wound carbon/glass polymeric composites as
           rocket motor thermal insulation

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      Authors: Jelena Rusmirović, Jela Galović, Marija Kluz, Srdja Perković, Saša Brzić, Marica Bogosavljević, Aleksandar Milojković, Tihomir Kovačević
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1541-S1554, November 2021.
      The study aim is to develop hybrid filament-wound polymeric composites based on flame retardant polyester resin (UPe) and multi-layer structured glass or combined carbon and glass fibers for use as ablative thermal insulation of rocket motor by wet filament winding technique. The composites have a multi-layered structure consisting of two layers of carbon (CF) or glass woven fabric (GF) and one layer of carbon or glass direct roving (CR or GR, respectively), repeated in three cycles. Structural analysis, performed using FTIR spectroscopy and dynamical-mechanical analysis, confirm highly polymerized network. Lower values of the tanδ peak height indicate improved interfacial adhesion between carbon/glass fibers and UPe. The improvements of thermal insulation index of 37% and erosion rate of 38.6% at 180°C are achieved for combined carbon/glass fiber–based composite compared to the neat UPe. Tensile and interlaminar shear properties are investigated according to the fiber orientation and the highest values of tensile and interlaminar shear strengths are obtained for composites with longitudinal orientation, 417.48 MPa and 22.30 MPa, respectively. Compared to the neat UPe, which degrades after 50 s at 3000°C, the composites are stable up to 192 s.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T11:56:41Z
      DOI: 10.1177/09673911211056787
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Mechanical properties of polyester/corn husk fibre composite produced
           using vacuum infusion technique

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      Authors: Shibly Shadik Mir Md, Ming Yeng Chan, Seong Chun Koay
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1532-S1540, November 2021.
      Issues pertaining to deforestation, environmental pollution and natural wastes are increasing day by day. These issues can be resolved by introducing a new composite material, in which natural waste is used as fibre and as a replacement of wood plastic composite. The different lengths (3, 6 and 9 cm) of corn husk fibre filled polyester composites were produced using the vacuum infusion method. Several mechanical properties of these polyester composites, such as tensile and flexural properties, were evaluated. The results revealed that both the tensile and flexural properties of polyester composites increased with increment of corn husk fibre length from 3 to 6 cm. However, the results decreased for 9 cm of fibre length filled composites. Similar trends were recorded after alkali treatment of the corn husk fibre filled polyester composites. The alkali treatment with sodium hydroxide had improved the tensile strength (33%), Young’s modulus (23%), elongation (14%), flexural strength (42%) and flexural modulus (8.5%) of the polyester/corn husk fibre composites with 6 cm of fibre length by enhancing the mechanical interlocking bonding between treated corn husk fibres and polyester.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T11:56:40Z
      DOI: 10.1177/09673911211056782
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Biotribological performance of medical-grade UHMW polyethylene-based
           hybrid composite for joint replacement

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      Authors: Omar Hussain, Babar Ahmad, Shahid Saleem Sheikh
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1424-S1431, November 2021.
      Ultra high molecular weight polyethylene (UHMWPE) is widely used for articulating surfaces in total hip and knee replacements. In the present work, the tribological properties of UHMWPE-based nano composites were studied in order to meet the demands of current bearing applications. UHMWPE matrix reinforced with 0.5, 1, and 2 weight percentage of alumina nano powder were fabricated by hot pressing. The dispersion and microstructure of composite material was established by X-ray diffraction (XRD) and scanning electron microscope (SEM) micrograph. The tests were carried out on a reciprocating sliding pin-on-disc tribometer at human body temperature (37±1°C) under dry and human serum lubricating environments for a normal load of 46 N and 52 N, a constant sliding speed of 4 mm. Under these testing conditions, it has been observed that the wear behavior of the developed composites improved with increase in weight percentage of alumina nano powder. The results show that at 52 N load, the maximum value of wear rate was 7.9x10−7 mm3/Nm and the minimum value 1.6x10−7 mm3/Nm was obtained. SEM was used to examine the worn surface and it was observed that human serum adheres to the surface of the composite pins upon sliding, resulting in the formation of a film which results in better wear resistance of the composite pins under human serum lubrication than dry sliding. This study implies that the use of nano alumina power will reduce the wear of UHMWPE based composite under human serum lubrication.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T11:32:27Z
      DOI: 10.1177/09673911211058088
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Free vibration analysis of industry-driven woven fiber laminated
           carbon/epoxy composite beams by experimental and numerical approach

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      Authors: Priyadarshi Das, Shishir K Sahu
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1371-S1385, November 2021.
      The free vibration study of industry-driven woven fibre laminated carbon/epoxy composite beam is addressed through experimental and numerical modal analysis in the present research work. The experimental modal analysis is performed using the vibration Fast Fourier Transform (FFT) analyser and the natural frequencies are realized in the PULSE environment. A linear beam model is simulated in ABAQUS finite element (FE) software, adopting a solid deformable 8-nodded element with five degrees of freedom (DOF) per node from the ABAQUS library for numerical computation of natural frequencies. A satisfactory agreement is achieved between the experimental and numerical results. The effects of ply-orientation, number of plies, lamination scheme and aspect ratios with different boundary conditions on the natural frequencies are studied. The results confirmed that the predicted vibration characteristics of laminated composite beams are sensitive to the adopted parameters for the investigation. The present study will help to understand the dynamic behaviour for laminated composite beams and serve as an experimental benchmark result within the frequency domain.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-12-06T11:22:07Z
      DOI: 10.1177/09673911211052825
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Free vibration characteristics of multi-core sandwich composite beams:
           Experimental and numerical investigation

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      Authors: Rajeshkumar Selvaraj, Kamesh Gupta, Shubham Kumar Singh, Ankur Patel, Manoharan Ramamoorthy
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1414-S1423, November 2021.
      This study investigates the free vibration responses of laminated composite sandwich beam with multi-cores using experimental and numerical methods. The laminated composite face sheets are made by using hand layup method. An experimental modal test has been carried for different configurations of multi-core sandwich beams under different end conditions. The single-core and multi-core sandwich beams has been modeled and the natural frequencies of sandwich beams are determined using ANSYS software. The numerical model is verified by comparing the obtained natural frequencies with experimental results. The numerical and experimental results indicate that the multi-core sandwich beam greatly influences the structural stiffness compared with single-core sandwich beam under different end conditions. Furthermore, the influence of several parameters such as the end conditions, thickness of the core layer, and stacking sequence on the natural frequencies of the various configurations of the multi-core sandwich beams are presented.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-27T10:16:11Z
      DOI: 10.1177/09673911211057679
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Microwave-assisted oxidative coupling of thiols using polystyrene
           supported bromoderivatives of 2-oxazolidone

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      Authors: Anjaly Mathew, Beena Mathew, Ebey P Koshy
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1351-S1360, November 2021.
      Polymer-supported reagents have become popular in synthetic organic chemistry over the past decades. But the kinetics of polymer-supported reactions is slow compared to solution phase synthesis because of the poor diffusion of the reactants through the macromolecular polymer matrix. This difficulty can be reduced to a great extent by performing polymer-supported reactions under microwave (MW) conditions. The present work is focussed on the design and development of an innovative, powerful, MW stable and recyclable polymeric reagent prepared by attaching bromoderivative of 2-oxazolidone into the macromolecular matrix of polystyrene. 3% cross-linked polystyrene was prepared by free radical aqueous suspension polymerization technique using tetra ethylene glycol diacrylate as the cross-linking agent and the resulting beads were functionalized by chloromethylation followed by reaction with 2-oxazolidone. Bromine functionality is introduced into the polymer by treating with bromine in carbon tetrachloride. The synthetic utility of the prepared polymeric reagent was demonstrated by the oxidative coupling of thiols to disulfides under MW irradiation. No over oxidation was observed in this protocol and the utilization of polystyrene support simplifies work up and product isolation. The synthesised polymeric reagent displayed good cyclic stability up to five cycles without any substantial decrease in bromine content and satisfactory storage stability under normal laboratory condition. Moreover this may be the first report that uses MW energy for the oxidation of thiols to disulfides using polymer-supported reagents.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-27T02:32:55Z
      DOI: 10.1177/09673911211048607
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Epoxy tooling: Technologies, developments, sustainability and future
           interest to industry 4.0

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      Authors: Gorka Díez-Barcenilla, José L Gómez-Alonso, Koldo Gondra, Ester Zuza
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1649-S1663, November 2021.
      The technology of epoxy tooling, at present under continuous development, is used for the rapid manufacture of cost-effective tools for small batch production. It is a valid alternative with no need for expensive investment in metallic moulds for the development of new products. Current investigations are focused on improvements to the production system, improved tool performance, the cost reduction of moulds and tool manufacturing sustainability. In this paper, both the advantages and the disadvantages of epoxy tooling in injection moulding, wax injection, metal stamping and hot embossing are compared with conventional techniques. Following a brief introduction of rapid tooling technologies, the latest advances of epoxy tooling and their implementation in different manufacturing processes are all analysed. These developments refer to the production of new ad-hoc epoxy composites, increased productivity using conformal cooling channels, the reduction of the tooling manufacturing costs through waste reuse and the emerging industry 4.0 technologies for smart manufacturing and tooling. The main objective is to identify both the challenges facing epoxy tooling techniques and future research directions.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-26T01:18:25Z
      DOI: 10.1177/09673911211059880
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Dynamic mechanical analysis of nylon 6 fiber-reinforced acrylonitrile
           butadiene rubber composites

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      Authors: C Rajesh, P Divia, S Dinooplal, G Unnikrishnan, E Purushothaman
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1328-S1339, November 2021.
      Dynamic mechanical properties of polymeric materials are of direct relevance to a range of unique polymer applications. The aim of the study is to investigate the dynamic mechanical properties of composites of short nylon 6 fiber with acrylonitrile butadiene rubber (NBR). The storage modulus (G′), loss modulus (G″), and the damping factor (tan δ) have been analyzed with reference to the effects of fiber loading, curing systems, and bonding agents over a range of temperature and at varying frequencies. The storage modulus increases with increment in fiber loading, whereas loss modulus and damping factor decrease. The glass transition temperature shifts to higher temperature upon increment in fiber loading. Dicumyl peroxide (DCP)–cured composites show higher storage modulus and lower damping than the corresponding sulfur-cured one. The addition of hexa-resorcinol and phthalic anhydride as bonding agents enhances the dynamic mechanical properties of the composites. The experimental results have been evaluated by comparing with Einstein, Guth, and Nielsen models.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-24T07:23:02Z
      DOI: 10.1177/09673911211046144
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Investigation on mechanical properties of hybrid aluminum/composite tubes
           manufactured by filament winding and hand lay-up

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      Authors: Hani Yadegari, Reza Taherian, Soheil Dariushi
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1486-S1497, November 2021.
      Nowadays, composite tubes have a wide range of applications in industries. Composite tubes are appropriate alternatives for metal energy absorbers. In this investigation, aluminum-composite tubes are made using Filament Winding (FW) and hand lay-up methods. Carbon Fiber (CF) and Glass Fiber (GF) are used in the FW method, and for the hand lay-up method, glass cloth is used. Five samples were fabricated with different stacking sequences, specimens with one, two, and three glass layers, one carbon layer, and hybrid carbon/glass layers. Characterization is performed by Scanning Electron Microscopy (SEM) analysis and mechanical tests (bending, compressive, and fatigue). The maximum bending force in the triple-layer GF tube is higher than other samples, while the maximum compressive force is observed in the hybrid carbon and GF tube. On the other hand, the fatigue strength of single-layer CF tubes is higher than single-layer GF tubes, so that the fracture cycles of single-layer CF tubes (600597) is significantly more than that of single-layer GF tubes (470068) at the force of 35 N. In addition, the compressive and bending energies absorption of samples were calculated. The hybrid carbon and GF tube absorbed higher energy than other samples. In GF and CF hybrid tubes, failure did not occur suddenly but gradually. This appropriate failure mechanism in the hybrid tube resulted in higher energy absorption and made it a suitable choice for industrial applications.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-19T03:47:30Z
      DOI: 10.1177/09673911211059875
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Electrospun polyethersulfone/Ag-Clinoptilolite to remove chemical oxygen
           demand from real wastewater

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      Authors: Mojgan Zendehdel, Faezeh Hossein Nouri
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1498-S1509, November 2021.
      Ag-Clinoptilolite/Polyethersulfone (PES/Clin/AgNPs) nanofiber was synthesized through the electrospinning method. The effect of solvent, the amount of Ag-Clinoptilolite, and PES were investigated. Parameters such as electric field, spinning distance, and concentration of the dope solution were studied in order to demonstrate their effects on the electrospinning ability and morphology of the nanofiber. The structure of PES/Clin/AgNPs nanofiber was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analyses. In the optimum conditions, the nanofibers could be prepared at the size of 250–800 nm. Then, their ability to remove chemical oxygen demand (COD) from real wastewater was studied. The result revealed about 85% removal of COD at pH = 10 and in 10 min for PES/Clin/AgNPs (25%). A successful fabrication method using low-cost natural zeolite and the green polymer was introduced. The reusability of the column was assessed.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-18T03:33:04Z
      DOI: 10.1177/09673911211060129
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Ageing of laser sintered glass-filled Polyamide 12 (PA12) parts at
           elevated temperature and humidity

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      Authors: Thomas Dooher, Edward Archer, Tom Walls, Alistair McIlhagger, Dorian Dixon
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1294-S1304, November 2021.
      Additive manufacturing is traditionally used to manufacture either prototypes or very small-scale demonstrators. In recent years though, it is being increasingly used to make low volume parts for the aeronautical and defence industry. One concern with laser sintered parts is that their relatively porous nature, means that they may be more susceptible to ageing than injection moulded parts. Parts were aged for 6 months in at different temperatures (18°C, 40°C, 50°C, 60°C, 80°C and 100°C) and in a humidity chamber at 60°C and 80% relative humidity. Each month samples were removed for characterisation. The testing included tensile testing, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and gas pycnometry. During ageing the samples displayed visible discolouration and embrittlement over the 6-month test period. This embrittlement was not observed in those samples aged at room temperature or an elevated humidity. The observed yellowing in the samples aged above ambient temperature is likely a result of the build-up unsaturated degradation products. No significant differences as a result of ageing were observed via DSC, TGA, SEM or gas pycnometry.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-15T10:48:26Z
      DOI: 10.1177/09673911211027127
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • The combined plasticization of jute and tung oil anhydride for jute fiber
           reinforced poly(lactic acid) composites

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      Authors: Ying Zhou, Can Chen, Lan Xie, Xiaolang Chen, Guangqiang Xiao, Shuhao Qin, Jianbing Guo, Yong He
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1569-S1577, November 2021.
      In this work, novel plasticizing biodegradable poly (lactic acid) (PLA) composites were prepared by melt blending of jute and tung oil anhydride (TOA), and the physical and mechanical properties of PLA/jute/TOA composites were tested and characterized. The impact strength of PLA/jute/TOA composites significantly increases with increasing the content of TOA. The SEM images of fracture surface of PLA/jute/TOA composites become rough after the incorporation of TOA. In addition, TOA changes the crystallization temperature and decomposition process of PLA/jute/TOA composites. With increasing the amount of TOA, the value of storage modulus (E′) of PLA/jute/TOA composites gradually increases. The complex viscosity (η*) values for all samples reduce obviously with increasing the frequency, which means that the pure PLA and PLA/jute/TOA composites is typical pseudoplastic fluid. This is attributed to the formation of crosslinking, which restricts the deformation of the composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-11T12:22:32Z
      DOI: 10.1177/09673911211057697
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • The effect of metalation processes on polymer morphology and conductivity
           properties

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      Authors: Oğuz Yunus Sarıbıyık, İlyas Gönül, Burak Ay, Serkan Karaca
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1340-S1350, November 2021.
      In this work, an insoluble three dimensional (3D) porous polymeric structure and their metal complexes were synthesised by the condensation reactions of meta(m)-phenylenediamine, para(p)-phenylenediamine and glutaraldehyde. The morphological and spectral features of the porous polymeric structures were determined using different analytical and spectroscopic methods, including field emission scanning electron microscopy, four-point probe electrical conductivity, photoluminescence spectroscopy, Fourier-transform infrared spectroscopy, surface area Brunauer–Emmett–Teller and magnetic and thermal behaviours. According to the obtained data, the shape, size and photoluminescence properties of the compounds, especially the conductivity, were clearly changed after the metalation processes.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-11T09:14:52Z
      DOI: 10.1177/09673911211048287
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Microencapsulated healing agents for an elevated-temperature cured epoxy:
           Influence of viscosity on healing efficiency

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      Authors: Habibah Ghazali, Lin Ye, Amie N Amir
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1317-S1327, November 2021.
      Among many applications, elevated-temperature cured epoxy resins are widely used for high-performance applications especially for structural adhesive and as a matrix for structural composites. This is due to their superior chemical and mechanical properties. The thermosetting nature of epoxy produces a highly cross-linked polymer network during the curing process where the resulting material exhibited excellent properties. However, due to this cross-linked molecular structure, epoxies are also known to be brittle, and once a crack initiated in the material, it is difficult to arrest the crack propagation. Earlier research found that the inclusion of encapsulated healing agents is able to introduce self-healing ability to the room-temperature cured epoxies. The current study investigated the self-healing behaviour of an elevated-temperature cured epoxy, which incorporated the dual-capsule system loaded with diglycidyl-ether of bisphenol-A (DGEBA) resin and mercaptan. The microcapsules were prepared by the in-situ polymerisation method while the fracture toughness and the self-healing capability of the tapered-double-cantilever-beam (TDCB) epoxy specimens were measured under Mode-I fracture toughness testing. We investigated the effect of temperature on viscosity of the healing agents and how these values influence the formation of uniform healing on the fracture surfaces. It was found that incorporation of the dual-capsule self-healing system onto an elevated-temperature cured epoxy slightly changed the fracture toughness of the epoxy as indicated by the Mode-I testing. In the case of thermal healing at 70°C, the self-healing epoxy exhibited a recovery of up to 111% of its original fracture toughness, where a uniform spreading of the healant was observed. The excellent healing behaviour is attributed to the lower viscosity of the healant at higher temperature and the higher glass transition temperature (Tg) of the produced healant film. The DSC analysis confirmed that the healing process was not contributed by the post-curing of the host epoxy.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-11-11T02:34:22Z
      DOI: 10.1177/09673911211045373
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Development and characterization of bio-composites using senegalia catechu
           resin

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      Authors: Vinayagamoorthy R, Venkatakoteswararao G
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1268-S1279, November 2021.
      Owing to the increase in demand on bio-degradable materials, the present researches focus on the development of materials with full degradability. This research is intended to develop a bio-resin–based composite from senegalia catechu gum for light load automotive applications. The bio-resin obtained from the plant is processed with commercial polyester in order to make it as a functional resin for composite preparation. The synthesized resin is made in the form of structural materials by adding jute reinforcements in varying proportions. An extensive study on the various characters in comparison with the synthetic resin–based composites has been done which includes mechanical strengths analysis and thermal characters investigation. It is revealed that the bio-resin–based composites are good against tensile, flexural and impact loads as compared to that of the synthetic resin composites. In addition, it has been witnessed that the material with 40% weight of jute fabric is apt for offering highest resistance against tensile, flexural and impact loads. Micro-structural investigations proved that the bio-resin–based composites are superior in reducing the flaws and enhancing the bonding of resin with fibres as compared to that of the synthetic resin-based composites. Further, the thermal characterization showed that the bio-resin–based composites have high thermal stability as compared to the synthetic composites, and hence, a positive sign is obtained for bio-resin–based composites in both mechanical and thermal characters.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-31T05:01:07Z
      DOI: 10.1177/09673911211054261
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Modification of physical and functional characteristics of chitin
           extracted from microwave-treated Nelumbo nucifera rhizome flour

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      Authors: Haq Nawaz, Rabia Mannan, Umar Nishan
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1257-S1267, November 2021.
      Chitin, a cell wall polysaccharide, extracted from Nelumbo nucifera rhizome (NNR), was subjected to microwave treatment to modify its physical and functional characteristics. The NNR flour was irradiated at different levels of the microwave treatment period (1, 2, 3, 4, and 5 min). Chitin was extracted from the native and microwave-treated samples and analyzed for physical and functional characteristics. The microwave treatment resulted in some variations in the extract yield, structure, morphology, and composition of chitin that were directly correlated with its functional properties. Regression analysis of the data showed a significant (p < 0.05) time-dependent linear decrease in extract yield, polynomial decrease in water-holding and swelling capacities, an exponential increase in oil holding, and an exponential decrease in iron-binding capacity of chitin extracted from microwave-treated flour. These variations in the studied functional properties may be due to microwave-induced hydrolytic degradation of chitin, structural rearrangements, and exposure of some lipophilic functional groups on the surface of chitin. The data would be a valuable contribution to the literature regarding microwave-induced modification in physical and functional characteristics of chitin present in N. nucifera rhizome and other plant-based biomaterials of industrial importance.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-30T03:49:49Z
      DOI: 10.1177/09673911211053304
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Preparation and characterization of pH-responsive ionic crosslinked
           microparticles of mercaptopurine to target ulcerative colitis

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      Authors: Huma Hameed, Khurram Rehman, Anam Hameed, Abdul Qayuum
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1248-S1256, November 2021.
      The objective of this study was the preparation of ionically crosslinked 6-mercaptopurine (6-MP) monohydrate microparticles through preparing polyelectrolyte complexes of drug and polymers. Polymers such as chitosan, casein, and carrageenan were used to prepare crosslinked microparticles, and sodium tripolyphosphate was used as crosslinker. Microparticles were characterized for their flow behavior, compressibility, percentage yield, micromeritic, and entrapment efficiency. Scanning electron microscopy was conducted to understand the surface morphology of the microparticles, and the result was correlated with the swelling index and percentage drug release. Mathematical modeling of drug release in order to determine the drug release kinetics was also determined to understand the mechanism involving the release of 6-mercaptopurine from the microparticles. The ionic crosslinked microparticles were in the range of 664 μm–798 μm particle size having good flow and compressibility properties with percentage yield were found to be from 77.5% to 87.5% in range. The entrapment efficiency for the formulations were found to be from 63.5% to 83.5%, with MCP-5 gave maximum entrapment efficiency of 83.5%. In vitro swelling and drug release studies were in accordance with the polymer properties following zero-order model with super-case transport II.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-28T02:19:09Z
      DOI: 10.1177/09673911211047338
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Development and performance analysis of wear resistant polypropylene
           composites filled with micro sized Linz–Donawitz sludge particulates

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      Authors: Abhilash Purohit, Alok Satapathy
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1235-S1247, November 2021.
      Integrated steel plants, in general, produce large amounts of solid wastes during the production of iron and steel. Linz–Donawitz sludge (LDS) is an industrial solid waste generated in huge quantities during steelmaking. These fine solid particles were recovered after wet cleaning of the gas emerging from LD converters. This work aims at processing, characterization, and wear response of a class of polypropylene composites utilizing LDS as a filler material. Mechanical properties of these thermoplastic composites were evaluated under standard test conditions. The actual and the theoretical density values of the polypropylene-LDS composites were measured using Archimedes’ principle and rule of mixture respectively. The micro-structural features of the worn surfaces of various particulate filled composite specimens were examined using scanning electron microscopy in order to ascertain the wear mechanisms. X-Ray Diffraction analysis was carried out to determine the phases and planes of the components present within a material. Sliding wear tests were conducted using Taguchi’s L25 orthogonal arrays over a range of sliding velocities (0.63–3.15 m/s), normal loads (5–25 N), sliding distances (500–2500 m), and LDS contents (0–20 wt.%). The sliding wear tests were performed on the prepared polypropylene-LDS composite specimens as per ASTM G99 using Taguchi’s Orthogonal Arrays followed by the parametric appraisal of the wear process by response surface methodology (RSM). Both Taguchi analysis and RSM suggest that the filler content and the sliding velocity are the most significant factors affecting the specific wear rate of the composite specimens. This work opens up a new avenue for the utilization of LD sludge as a potential filler material.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-25T06:10:16Z
      DOI: 10.1177/09673911211051569
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Preparation of n-type polyaniline/hexagonal boron nitride composites with
           a large thermoelectric power factor

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      Authors: Volkan Ugraskan, Ebubekir Ceran, Ozlem Yazici
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1227-S1234, November 2021.
      In the present study, it was aimed to investigate the thermoelectric (TE) properties of polyaniline/hexagonal boron nitride (PANI/h-BN) composites. First, h-BN was synthesized from boric acid and urea. Then, PANI-HCl was synthesized by oxidative chemical polymerization. Finally, the composites were prepared using different weight ratios of h-BN. The composites were characterized using attenuated total reflection accessory attached Fourier-transform infrared spectroscopy, UV-vis spectroscopy, X-ray diffraction, and scanning electron microscopy/energy dispersive X-ray analyzer. TE investigation of the composites showed that the addition of h-BN significantly contributes to the TE properties of PANI-HCl. The addition of h-BN increased the power factor of PANI-HCl from 0.07 μWm−1K−2 to 143.05 μWm−1K−2. Furthermore, all the composites showed negative Seebeck coefficients which are the characteristics of n-type semiconductors.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-22T04:02:20Z
      DOI: 10.1177/09673911211042504
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Combination of silk fabric and natural rubber for the development of green
           composites: Influence of curing on mechanical and thermal properties

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      Authors: Thanuj Kumar M, Sanga Shetty S G, Ekwipoo Kalkornsurapranee, Ladawan Songtipya, Yeampon Nakaramontri, Jobish Johns
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1204-S1215, November 2021.
      Unmodified natural rubber is not suitable for any elstomeric applications. Therefore, it is appropriate to modify natural rubber chemically to enhance the stability, which can be termed as vulcanization. Incorporation of fibers/fabrics is a common method to increase the stability of natural rubber along with chemical modification. Natural rubber-based composites have been prepared by the addition of silk fabric into natural rubber. The matrix material for the composite is glutaraldehyde cured natural rubber. Silk is an ecofriendly and biodegradable material with excellent tensile strength. When such kind of fabric is introduced into the vulcanized rubber as the matrix, all the physical properties were found to be enhanced considerably. Tensile properties in terms of ultimate tensile strength, elongation at break, and modulus of elasticity are measured for the composites of natural rubber/silk fabric at various glutaraldehyde concentrations. Thermogravimetric analysis and temperature scanning stress relaxation techniques are employed to evaluate the thermal stability of the resulting composites. Effects of glutaraldehyde addition on the physical properties of the composite were studied in detail. Considerable enhancement in the stability of natural rubber in terms of tensile properties, thermal stability, and solvent resistance is noticed up on the incorporation of silk fabric as well as glutaraldehyde curing.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-21T11:31:25Z
      DOI: 10.1177/09673911211049103
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • Study of heat and sound insulation for polymeric composites reinforced
           with nano clay

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      Authors: Rana M Salih
      Abstract: Polymers and Polymer Composites, Volume 29, Issue 9_suppl, Page S1216-S1226, November 2021.
      Composite materials were prepared using epoxy as a matrix and nanoclay as a reinforcement with weight fractions 5% and 10%, using hand lay-up as a preparation technique. An unreinforced epoxy cast was also prepared for comparison. Heat and acoustic insulation were studied, in addition to tensile, compression, and impact tests. The results showed that the sound levels were the highest in the unreinforced specimen, and decreased gradually with nanoclay, suggesting that the nanoclay have impeded the path for sound waves transmission. The same behavior was observed with thermal conductivity. The tensile strength for the 5% wt. specimens were about 40% higher than that of the 10% wt. specimens, and about 60% higher than the unreinforced epoxy. The Young's modulus was 1.899 MPa, 3.25 MPa, and 4.143 MPa for the 5%, 10%, and unreinforced epoxy, respectively. Impact and compressive strengths were directly proportional with nano clay content. Scanning electron microscopy was used to reveal the microscopic details. The results prove that the addition of nanoparticles must be optimized to get the desired results.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-21T07:52:03Z
      DOI: 10.1177/09673911211051164
      Issue No: Vol. 29, No. 9_suppl (2021)
       
  • A comprehensive overview of dual-layer composite membrane for air (O2/N2)
           separation

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      Authors: Syed Shujaat Karim, Sarah Farrukh, Arshad Hussain, Tayyaba Noor, Mohammad Younas
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The separation of air (O2/N2) via a polymeric membrane has recently piqued the interest of academic researcher as well as the industrial sector. Because of its remarkable characteristics, the polymeric membrane has emerged as one of the innovative and fast growing technology. However, two major problems faced by membrane technology, which hinder its growth in the commercial sector are, 1): The trade-off between permeability and selectivity. 2): Maintaining physical and chemical structural stability in a long-term commercial scale process. Recent advancements in membrane material, structural, and process design have enabled the development of dual-layer composite (DLC) membranes. This concept combines the benefits of both thinner mixed matrix membranes (MMMs) based active layer and porous support substrate. Due to these properties, the membrane exhibits higher perm-selectivity with enhanced mechanical strength as compared to single layer polymeric membrane. This review article mainly focused on the developmental progress of DLC membrane throughout the years. In which membrane structural details, selection criteria, fabrication methodologies, application [e.g., air (O2/N2) separation] were critically reviewed. In addition, challenges arising in the DLC membrane production and future prospects for the development of these membranes were also thoroughly discussed in this literature. This creates a paradigm for future research in the commercial development of these membranes for the air (O2/N2) separation process, which can be utilized in both medical and industrial sectors.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T11:04:44Z
      DOI: 10.1177/09673911211045852
       
  • Accelerated aging and characterization of HDPE pin type insulators
           (15 kV)

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      Authors: Cynthia DC Erbetta, Maria Elisa SR Silva, Roberto FS Freitas, Ricardo G Sousa
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The study of the behavior of polymeric material used for insulators in the electrical system is extremely important in order to evaluate their lifetime as well as their performance when exposed to different environmental conditions. In the present work, the behavior of high-density polyethylene (HDPE) pin type insulators (15 kV), under accelerated aging conditions, was studied. Samples were exposed to aging, for 200 h, 1000 h, and 2000 h, in accelerated weathering chambers, according to two different methods. In Method 1, the parameters were established based on natural aging in location conditions, and in Method 2, ASTM G155 standard parameters were used. All samples were characterized by rheometry, Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The accelerated aging conditions, used in Methods 1 and 2, affected the aging of HDPE pin type insulators samples differently, the changes being more intense in Method 1.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T10:49:04Z
      DOI: 10.1177/09673911211047682
       
  • The effects of the metal pigment, adsorbent, extractant and their feeding
           methods on the properties of
           polycarbonate/acrylonitrile–butadiene–styrene composites

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      Authors: Xiaolin Liu, Lei Zhou, Jian Chen
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim of the present work is to upgrade the functionality and applicability of polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) blends by means of a blending technique. Metallic glossy PC/ABS composites with low odour were prepared by adding metallic pigment, adsorbent and extractant into the PC/ABS composite matrix. The effects of the metal pigment, extractant, adsorbent and processing technology on the volatile organic compounds (VOC), condensable substances (FOG) and odour of PC/ABS composites were studied systematically. It was found that upon increasing the content of the metallic pigments, the VOC, FOG and odour of the PC/ABS composites increase rapidly. The adsorbent and extractant can effectively improve the VOC, FOG and odour. When the extractant and adsorbent were used at the same time, the method of adding extractant and adsorbent from the main and the secondary feeding port, respectively, was significantly superior to the method of adding the extractant and adsorbent from the main feeding port together in reducing the VOC, FOG and odour of PC/ABS composites, which displayed a good synergistic effect. When the adsorbent and extractant content are 1.5 and 5.0 parts per hundreds of resin (phr), respectively, the obtained composites have good metallic lustre and environmental friendliness (odour level = 2.0, VOC and FOG: not detected).
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T08:59:37Z
      DOI: 10.1177/09673911211042514
       
  • Structural, transport, morphological, and thermal studies of nano barium
           titanate–incorporated magnesium ion conducting solid polymer
           electrolytes

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      Authors: Jayanthi S, Kalapriya K
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      A new series of nanocomposite polymer electrolytes (NCPEs) was prepared using poly(vinylidene fluoride–co–hexafluoro propylene) P(VdF-HFP) as polymer, magnesium triflate (MgTr) as salt and nano-sized barium titanate (BaTiO3) (
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T06:02:40Z
      DOI: 10.1177/09673911211047325
       
  • Effects of silane coupling agent modifications of hollow glass
           microspheres on syntactic foams with epoxy matrix

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      Authors: Rui Li, Guisen Fan, Peng Wang, Xiao Ouyang, Ning Ma, Hao Wei
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      A syntactic foam was prepared from an epoxy resin matrix and modified hollow glass microsphere fillers. Modification by silane coupling agents with different molecular structures was analyzed, and the optimal content of the silane coupling agent was determined. The results demonstrated that all silane coupling agents enhanced the adhesion between the hollow glass microspheres and epoxy resin matrix, resulting in enhanced water absorption, compressive performance, tensile performance, and bending performance compared to those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end groups, the one with a sulfhydryl end group exhibited optimal modification for hollow glass microspheres. Among the silane coupling agents with different backbone structures, the one with silanol groups exhibited the optimal modification of hollow glass microspheres. Additionally, the performance of the syntactic foams was optimal when 6% of the silanol-containing coupling agent was used. The results demonstrated that syntactic foams prepared with hollow glass microspheres modified by silane coupling agents exhibited improvements in water absorption, compressive performance, tensile performance, and bending performance, compared with those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end structures, the one with a sulfhydryl group as end group showed the best modification effect on hollow glass microspheres. The water absorption was 0.35%, the compressive strength was 62.15 MPa, the tensile strength was 40.15 MPa, and the bending strength was 53.17 MPa. Among silane coupling agents with different backbone structures, the one with silanol groupsbonds showed the best results. Its compressive strength was up to 64.15 MPa, the tensile strength was 35.47 MPa, and the bending strength was 53.99 MPa.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T05:19:37Z
      DOI: 10.1177/09673911211046796
       
  • A hybrid optimization technique to control the machining performance of
           graphene/carbon/polymer (epoxy) nanocomposites

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      Authors: Jogendra Kumar, Rajesh K Verma, Arpan K Mondal, Vijay K Singh
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The machining behavior of polymers is substantially different from metal and their alloys due to non-homogeneity and anisotropy. This article describes a hybrid optimization method during machining (milling) of epoxy nanocomposites reinforced by graphene oxide/carbon fiber (G/CF). The milling experimentation was staged according to the L9 orthogonal array of the Taguchi theory. The control of process constraints, namely, cutting speed (Vc), feed (F), depth of cut (D), and G weight % (G) have been appraised to acquired the desired machining response such as material removal rate (MRR), cutting force (Fc), and surface roughness (Ra). Grey-coupled principal component analysis (grey-PCA) effectively tackled the response priority weight during aggregation of conflicting responses. The optimal condition secured by the grey-PCA module are found as Vc = 25.12 m/min, F = 240 mm/min, D = 0.5 mm, and G = 1 %. The supplement of graphene enhances the machining characteristics of the nanocomposites, which in turn, minimizes the damages that occur during the milling process. Scanning electron microscopy (SEM) analysis was conducted for microstructure investigation of the machined component. The findings of confirmatory experiments show good agreement with the actual ones. The preferred solution values of grey-PCA are observed as 1.027, which confirms the proposed technique’s higher practicability.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-19T01:53:45Z
      DOI: 10.1177/09673911211046789
       
  • Synthesis of thermally protective PET–PEG multiblock copolymers as
           food packaging materials

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      Authors: Tuğba Güngör Ertuğral, Cemil Alkan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      One of the storage conditions affecting quality of food stuffs due to short shelf life is temperature. Thermal insulation can be achieved by adding phase change materials (PCMs) to packaging materials. PCMs store and release latent heat of phase change during melting and crystallization operations, respectively. Thus, they can provide thermal protection for packaged foods. The aim of this study is to prepare new food packaging materials poly (ethylene terephthalate)–poly (ethylene glycol) (PET–PEG) multiblock copolymers as solid–solid phase change materials (SSPCM) as potential food packaging materials with thermal energy storage (TES) property. Polyesterification was carried out with PEG at different average molecular weights (1000, 4000 and 10,000 g/mol), ethylene glycol (EG) and terephthaloyl chloride (TPC). Synthesized PET–PEG multiblock copolymers were characterized using Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) methods. The crystal structures of PET–PEG multiblock copolymers were characterized by polarized optical microscopy (POM) and their surface properties were determined by performing contact angle tests. TES capacity of the PET–PEG multiblock copolymers was found in range of 26.1–150.5 J/g. Consequently, this study demonstrates the potential of PET–PEG multiblock copolymers suitable for effective thermal preservation in packaging material applications to maintain the quality of packaged food stuffs.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-18T09:57:06Z
      DOI: 10.1177/09673911211045683
       
  • Micromechanical approach to viscoelastic stress analysis of a pin-loaded
           hole in unidirectional laminated PMC

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      Authors: Arash Reza, Mohammad Shishesaz, Hamid M Sedighi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This paper aims to investigate the effect of viscoelastic behavior of polymer matrix of unidirectional fiber-reinforced laminated composite on stress distribution around the pin-loaded hole under tensile loading. The Laplace transform is used to prevent the integral form of matrix governing stress-strain relation. Applying a micromechanical model, all equilibrium equations for the fibers are written analytically in the Laplace domain. The numerical algorithm of Gaver–Stehfest is implemented, and the governing equations were solved at any given time to extract the concerned results in the time domain. The obtained results are validated against the Finite Element Method results obtained through ANSYS software. Moreover, a comparison of the results of this study at the time equal zero with elastic solutions of other references showed a good agreement. The results revealed that in the long term, the maximum tensile load in the intact fiber around the pinhole was enlarged and the tensile load in fibers far from the pinhole slightly was decreased. Moreover, the location of the maximum axial load that had occurred on pinhole edges was moved slightly toward the center over time.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-18T07:19:10Z
      DOI: 10.1177/09673911211047340
       
  • Evaluation of mechanical performance and water absorption properties of
           modified sugarcane bagasse high-density polyethylene plastic bag green
           composites

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      Authors: Ruey Shan Chen, Yao Hsing Chai, Ezutah Udoncy Olugu, Mohd Nazry Salleh, Sahrim Ahmad
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Enormous amounts of plastic wastes are generated worldwide and the approaches related to plastic recycling or reusing have become the research focus in the field of composite materials. In this study, green composites were prepared via melt-blending method using high-density polyethylene (HDPE) sourced from plastic bags as a matrix and sugarcane bagasse (SCB) fiber as reinforcing filler. The effects of fiber loading (5, 10 and 15 wt%) and fiber modification on the mechanical and dimensional stability (weight gain by water absorption) properties of the green composites were investigated. Results showed that the inclusion of SCB fiber into recycled HDPE matrix increased the composite stiffness but decreased the mechanical strength and resistance to water absorption. With the fiber modification through alkali treatment, the mechanical strength was remarkably improved, and the modulus and water absorption of the composites were found to be reduced. From the finding, it can be concluded that the prepared green composites free of coupling agent could add value to the plastic and agricultural wastes, and serve a potential candidate to replace some conventional petroleum-based composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-18T05:53:17Z
      DOI: 10.1177/09673911211049058
       
  • Rice waste–based polymer composites for packaging applications: A
           review

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      Authors: Waham Ashaier Laftah, Wan Aizan Wan Abdul Rahman
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Rice wastes are abundant, low-cost, cellulosic-based materials. The potential of using rice waste such as husk, straw, and bran in bio-composite production is a crucial target of the composite industry. Chemical composition is the main factor that offers diverse possible applications of rice wastes in bio-composite-based materials. Eco-friendly products of bio-composite polymers can be produced by reinforcing and filling polymer matrices with high cellulosic content materials such as rice waste. From manufacturing point of view, rice wastes can be used to reduce the production cost of polymer-based products and meet the requirements for green packaging materials.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-14T11:55:47Z
      DOI: 10.1177/09673911211046775
       
  • Investigation of mechanical properties and biodegradability of
           compatibilized thermoplastic starch/ high impact polystyrene blends
           reinforced by organophilic montmorillonite

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      Authors: Nour El Houda Aouadi, Abdelhak Hellati, Nizamudeen Cherupurakal, Melia Guessoum, Abdel-Hamid I Mourad
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This work consists of preparation and characterization of composites produced from thermoplastic starch (TPS) and high impact polystyrene (HIPS). Due to the immiscibility of the system (TPS/HIPS), it was necessary to incorporate concentrations of 1, 2 and 3% of an organophilic montmorillonite (MMT) to improve the properties of the mixtures, in particular their rigidity. The composites thus prepared were characterized using XRD, FTIR, mechanical test, degree of swelling in water and biodegradability. The results show that the addition of MMT improves the mechanical properties of the mixtures such as the tensile strength and the Young’s modulus by 5% and 10%, respectively. In contrast, the resilience of the system has significantly decreased. Moreover, for 3% of MMT, the composites biodegradability is enhanced by 15% when compared to the TPS/HIPS mixture without MMT.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-10-14T11:49:24Z
      DOI: 10.1177/09673911211046803
       
  • Comparative study of flexural and physical properties of graphite-filled
           

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      Authors: Oluwaseun Ayotunde Alo, Iyiola Olatunji Otunniyi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polypropylene/epoxy/synthetic graphite (PP/EP/SG) and high-density polyethylene (HDPE/EP/SG) composites were prepared by melt mixing followed by compression molding. The immiscibility of the polyolefins with epoxy was confirmed by thermogravimetric analysis. Scanning electron microscopy (SEM) studies showed that HDPE/EP blend exhibits inferior interfacial adhesion between the component polymers compared to PP/EP blend. Also, the effect of SG content on flexural properties, density, moldability, water absorption, and porosity of the PP/EP/SG and HDPE/EP/SG composites was investigated. For both PP/EP/SG and HDPE/EP/SG composites, flexural modulus, density, and porosity increased with increase in SG content. For PP/EP/SG composites, the water absorption decreased from 0.154% at 30 wt% SG to 0.072% at 70 wt% SG. Further increase in SG content to 80 wt% caused an increase in water absorption. On the other hand, water absorption for HDPE/EP/SG increased with SG content all through. At the same filler loadings, PP/EP/SG composites showed lower density and porosity and performed better in terms of flexural modulus and water absorption compared to HDPE/EP/SG composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-09-27T02:49:21Z
      DOI: 10.1177/09673911211047027
       
  • Effects of recovered brown alumina filler loading on mechanical,
           hygrothermal and thermal properties of glass fiber–reinforced epoxy
           polymer composite

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      Authors: P Sabarinathan, VE Annamalai, K Rajkumar, K Vishal
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This study investigates the efficiency of recovered brown alumina (RBA) particles filled in epoxy glass-fiber composites. The RBA particles were obtained from grinding wheel rejects with the help of the mechanical crushing process. Recovered particles finer than 120 grit were used as particulate filler for composite preparation. Composites were processed through a hand-layup technique by varying RBA filler loading percentages (0, 5, 10, 15, and 20 wt.%) in a glass fiber–reinforced epoxy matrix. Physical, mechanical, water absorption, and thermal properties of the composites were tested experimentally. By suitable addition of RBA, it is possible to tailor the shore-D hardness, tensile modulus, flexural strength, flexural modulus, and maximum degradation temperature. The 20%-filled RBA composite shows the maximum flexural strength of 382 MPa, and the shore-D hardness value was 85. The fracture surface shows a failure mechanism dominated by matrix cracking and debonding of fiber/particles from the interface. Hygrothermal testing of the RBA20-filled composite reveals 9% and 4% reduction in tensile and flexural properties. The thermal stability of the glass fiber–reinforced composite improves as the filler percentage increases. Maximum thermal stability of 435°C was observed in 20%-filled RBA polymer composite.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-09-23T10:13:16Z
      DOI: 10.1177/09673911211046780
       
  • Development of poly (vinylidene fluoride)/silver nanoparticle electrospun
           nanofibre mats for energy harvesting

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      Authors: Roopa Thotadara Shivalingappa, Hebbale Narayana Rao Narasimha Murthy, Pradeep Purushothaman, Prasanna Badiger, Swapnil Savarn, Utsav Majumdar, Gangadhar Angadi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Energy harvesting using piezoelectric materials finds attention of researchers due to miniaturisation. Polyvinylidene fluoride (PVDF) is one such polymeric material with high piezoelectric and pyroelectric properties and hence is used for sensors, actuators, energy harvesting and biomedical devices. This study reports electrospinning of PVDF/Ag nanoparticles (AgNP) nanofibre mats for energy harvesting. Nanofibre mats were prepared by adopting voltage (20 kV), flow rate (1.5 mL/hour) and tip to collector distance (19 cm). The fibre mats were characterised using Fourier-Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). FTIR and XRD results showed 11.84% and 36.36% increase in β-phase and crystallinity, respectively, due to the addition of 1.5 wt. % AgNP to PVDF. SEM micrographs showed decrease in bead formation and increase in fibre diameter from 40 nm to 355 nm due to the addition of AgNP. Sensitivity and voltage output were studied. The fibre mats were used for development of a miniature burglar alarm system, and its response to the applied pressure was tested.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-09-16T07:46:12Z
      DOI: 10.1177/09673911211042005
       
  • Practice of Taguchi design of experiments in the valuation of mechanical
           behavior of rigid polyurethane foam composites

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      Authors: Raminder Kaur, Mukesh Kumar
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In the present study, Taguchi design of experiments (DOEs) L18 orthogonal array has been used for the investigation of the mechanical behavior of rigid polyurethane foam (RPUF) composites. The outcome of the process parameters such as polyol, filler, surfactant, catalyst, blowing agent, and anti-flaming agent on the mechanical properties, such as tensile, flexural, and compressive strengths and hardness (Shore D) of RPUF composites, has been examined, and the resulted data were analyzed by means of Taguchi design of experiments. The raw data for the average values of the mechanical properties and the signal-to-noise (S/N) ratio for each parameter were evaluated at three levels, and the analysis of variance (ANOVA) and optimum process parameters are determined. The confirmation experiments were performed for the validation of the improved performance and to measure the contribution of individual parameter on the responses. The confirmation experiments revealed the average tensile strength, average compressive strength, average flexural strength, and average hardness (Shore D) as 5.24 MPa, 6.37 MPa, 12.28 MPa, and 72.43, respectively, which fall within the 95% confidence interval of the anticipated optimum process parameters.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-09-02T03:12:56Z
      DOI: 10.1177/09673911211041357
       
  • Efficiency of castor oil–based polyurethane foams for oil sorption S10
           and S500: Influence of porous size and statistical analysis

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      Authors: Fillip C Alves, Vanessa F dos Santos, Francisco M Monticeli, Heitor Ornaghi, Hernane da Silva Barud, Daniella R Mulinari
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This study evaluates the efficiency of castor oil–based polyurethane foams for oil sorption S10 and S500, focusing on the influence of the pores’ size. Different foams were produced by varying the polyol: isocyanate ratio (1:0.3; 1:0.5; 1:1.0; 1:1.5; and 1:2.0). The physicochemical properties, morphology, density, and Hg porosity were determined. The sorption capacity was influenced by exposure time, oil viscosity, and concentration of the reagents, considering variations in the hydrophobicity, void content, and morphology. The results showed that the foam produced at an in the same mass proportion (PUC) has a higher sorption capacity in exposure time from 25 to 40 h due to higher void content and larger pore diameter size. It was observed that the lower viscosity of S10 diesel contributes to the higher sorption efficiency compared to S500 one. The Taguchi method corroborated the mentioned results, indicating a higher sorption trend by varying the reagent concentration and exposure times.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-28T11:16:15Z
      DOI: 10.1177/09673911211040360
       
  • Charge transport mechanism in dodecylbenzenesulfonic acid doped
           polyaniline/carbon black composites

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      Authors: Ariba Bibi, Abdul Shakoor
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Dodecylbenzenesulfonic acid (DBSA) doped polyaniline and carbon black (CB) composites (PANI-DBSA/CB) were synthesized by in-situ polymerization of aniline in the aqueous dispersion of carbon black (CB) in the presence of ammonium persulfate (APS) as an oxidant. Various composite samples with varying amounts of CB (1 wt% and 2 wt%) were synthesized and were characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD studies confirmed the formation of the well-organized and semi-crystalline structure of the composites. SEM analysis revealed the increase in grain size and the granular structure of the synthesized composites. DC conductivity was measured in the temperature range from 300 K to 393 K using two probe methods. An increase in DC conductivity was found on the inclusion of carbon black at all temperatures and the most probable model of charge transport was found to be three-dimensional variable range hopping (3D-VRH). As the concentration of CB in the composites increased, activation energy was found to be decreased. The density of states, hopping length, and hopping energy were calculated, respectively, and were found to be influenced by CB incorporation.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-18T01:57:59Z
      DOI: 10.1177/09673911211040376
       
  • Experimental and artificial neural network approach for prediction of
           dynamic mechanical behavior of sisal/glass hybrid composites

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      Authors: Heitor Luiz Ornaghi, Francisco M Monticeli, Roberta Motta Neves, Ademir José Zattera, Sandro Campos Amico
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The dynamic mechanical behavior (storage modulus, loss modulus, and tan δ) of hybrid sisal/glass composites was investigated in the temperature range of 30–210 °C, for two different volume percentages of reinforcement along with the different ratios of sisal and glass fibers. Based on the experimental outcome, an artificial neural network (ANN) approach was used to predict the dynamic mechanical properties followed by a surface response methodology (SRM). The ANN analysis showed an excellent fit with the storage modulus, loss modulus, and tan δ experimental data. In addition, the fitted curves with the ANN approach were used to propose equations based on SRM. The simulation result has shown that the ANN is a potential mathematical tool for the structure–property correlation for polymer composites and may help researchers in the development and application of their data, reducing the need for long experimental campaigns.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-14T09:33:29Z
      DOI: 10.1177/09673911211037829
       
  • Chemical and biological characterization of sulfated chitosan oligomer as
           heparin mimics

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      Authors: Samet Kocabay, Mehmet Refik Bahar, Suat Tekin, Recep Akkaya, Birnur Akkaya
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In the present study, chitosan oligomer was modified to sulfated chitosan oligomer (ShCsO) to mimic heparin. Its chemical structure was determined by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis. The results showed that the FT-IR spectrum band at 799 cm−1 corresponds to C–O–S and that at 1212 cm−1 corresponds to S=O bond stretching, which prove that the sulfate groups are incorporated into chitosan oligomer successfully. The antimicrobial activity of ShCsO against to Bacillus subtilis in 1% concentration was 89.1 ± 1.7%. The IC50 (μg/ml) of ShCsO was 67.75, 56.07, 85.47, and 84.68 for A2780, MCF-7, DU-145, and HepG2, respectively. The results show that this newly synthesized material is a potential candidate to heparin-like chitosan derivatives. According to the literature, it was the first time that chitosan oligomer was modified to mimic heparin.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-12T05:17:16Z
      DOI: 10.1177/09673911211035068
       
  • Antibacterial properties of a novel nano-silver loaded
           poly(styrene-co-acrylic) composites

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      Authors: Ruge Cao, Xuqing Zhai, Xueyang Li, Xiaoyu Zhao
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      To prevent microbial contamination in foods and medical tools, we prepared a novel antibacterial material nano-silver loaded poly(styrene-co-acrylic) (nAg-PSA) composites by in situ reductions. The nAg-PSA was characterized by scanning electron microscope, transmission electron microscopy, energy dispersive X-ray spectroscopy and thermogravimetric analysis. The antibacterial properties of nAg-PSA against Escherichia coli and Staphylococcus aureus were systematically evaluated, and the underlying mechanism was investigated. Results showed that the silver nanoparticles were successfully loaded onto PSA microspheres, highly dispersed on the surface of nAg-PSA nanoparticles. The nAg-PSA nanoparticles all showed significant antibacterial effects, among which nAg-PSA4 had maximum diameters of inhibition zones against the Gram-negative E. coli (1.18 mm) and the Gram-positive S. aureus (1.29 mm), respectively, which closely related to the size and density of silver nanoparticles covered on the surface.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-11T09:46:30Z
      DOI: 10.1177/09673911211037499
       
  • Physicochemical properties of chitosan–magnetite nanocomposites
           obtained with different pH

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      Authors: Christian Chapa González, Javier Ulises Navarro Arriaga, Perla Elvia García Casillas
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The physicochemical properties of the nanoparticle surface determine the performance of nanocomposites in biomedical applications such as their biodistribution and pharmacokinetics. The physicochemical properties of chitosan, such as apparent charge density and solubility, are pH dependent. Similarly, Fe3O4 nanoparticles are susceptible to variations in their physicochemical properties due to changes in pH. In this work, we evaluated the physicochemical properties of chitosan–magnetite nanocomposites that were suspended at pH 7.0, 9.0, and 11.0 to determinate the effect on particle size, zeta potential, and mass percentage of the polymeric coating, in addition to the crystalline phase and magnetic properties of magnetite phase. X-ray diffraction results exposed that the present phase was magnetite with no other phases present and that the crystallite size was between 10.8 and 14.1 nm. Fourier transform infrared verified the chitosan functional groups in treated samples while the percentage of mass determined by TGA found to be nearly 9%. Scanning electron microscopy micrographs corroborated the spherical shape of the bare and chitosan-coated nanoparticles. Dynamic light scattering results showed that chitosan coating modifies the zeta potential, going from a potential of −11.8 mV for bare particles to −3.0 mV (pH 11). Besides, vibrating sample magnetometer measurements showed that coercivity remained very low, which is desirable in biomedical applications.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-11T05:19:45Z
      DOI: 10.1177/09673911211038461
       
  • Synthesis and characterization of polypyrrole/molybdenum oxide composite
           for ammonia vapour sensing at room temperature

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      Authors: Mohd Urooj Shariq, Ahmad Husain, Mahfoozurrahman Khan, Anees Ahmad
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, polypyrrole (PPy) and polypyrrole/molybdenum oxide composite (PPy/MoO3) were synthesized by the chemical oxidative method in an aqueous medium, using anhydrous ferric chloride (FeCl3) as an oxidant. The successful preparation of materials was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance electron microscopy (TEM). PPy and PPy/MoO3 were converted into pellets which were used as the sensor. A four-in-line probe device was used for studying DC electrical conductivity–based ammonia vapour–sensing properties at three different ammonia concentrations, that is, 1 M, 0.5 M and 0.1 M. The PPy/MoO3 sensor showed much-improved sensing performance than the PPy sensor in terms of % sensing response and reversibility. PPy/MoO3 sensor showed excellent selectivity for ammonia vapours against various VOCs. The % sensing response of PPy/MoO3 sensor towards ammonia was found to be 2.19, 2.50, 3.16, 3.87, 4.1, 5.15, 6.19, 6.55 and 7.77 times greater than ethanol, methanol, acetone, acetaldehyde, formaldehyde, toluene, benzene, chloroform and n-hexane, respectively. In the end, a sensing mechanism was also proposed, which is based on rapid adsorption–desorption of ammonia molecules on the PPy/MoO3 sensor’s surface.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-02T12:04:44Z
      DOI: 10.1177/09673911211036589
       
  • Effect of alkaline treatment on mechanical properties of composites:
           Unsaturated polyester reinforced ZrO2/jute and sisal

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      Authors: Bhabatosh Biswas, Nil Ratan Bandyopadhyay, Gurudas Mandal, Arijit Sinha
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Alkali treated (5 wt. % alkali was used on the total weight of the alkali solution and the treatment time was 2 h) discontinuous cellulosic fiber (jute and sisal were used as cellulosic fibers and 35 wt. % filler content was incorporated) reinforced chemically modified ZrO2 (ZrO2 was used as 10 wt. % of total filler content. In this context, it is worthwhile to mention that when both fillers were used, the fiber content was taken in the weight ratio of 1:1.) dispersed hybrid unsaturated polyester composites were fabricated by a compression molding technique. The mechanical behavior of the fabricated composites was evaluated at the sub-micron scale by nanoindentation (indentation with an applied load on the composites surface at the nano-metric range) or depth-sensing instrumented indentation technique. The significant effect of incorporation of the dispersing phases within the unsaturated polyester matrix with respect to mechanical properties at microstructural length scale was observed. A marked improvement in the nanoindentation-derived parameters viz., nanohardness, reduced modulus, elastic recovery, and indentation creep was observed which may be attributed due to the influence of fillers inclusion within the unsaturated polyester matrix. An extensive effort was laid to analyze the dynamic mechanical properties using the sinus indentation mode associated with nanoindentation measurements to further correlate the influence of fillers addition with the indentation-derived parameters.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-08-02T02:14:41Z
      DOI: 10.1177/09673911211033949
       
  • Effect of size and shape of nanofillers on electrostatic and thermal
           behavior of epoxy-based composites

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      Authors: Mihir N Velani, Ritesh R Patel
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The role of nanodielectrics in the electrical power system is becoming crucial owing to its superior properties and potential applications in the field. Yet, the materials face limited breakdown strength and thermal properties. Further, the nanodielectrics have not found a comprehensive commercial platform because of the costly manufacturing process, and characterization and testing facilities. Therefore, to reduce the involved cost, in this work, an FE (finite element) based computational technique has been implemented to visualize the effect of shape, size, and filler concentration under the application of high voltage (HV). The epoxy-based nanodielectrics have been modeled incorporating a range of different shapes and size nanofillers—Al2O3, BN, BeO, SiO2, and TiO2. The paper discusses the 2D-analysis of the modeled nanodielectric in the steady-state electrostatic fields and thermal domains. It shows the insights of the nanofillers’ choice to ensure a perfect blend of electrical and thermal properties. The epoxy with square-shaped BeO fillers showed a rise in the electric field of nearly 1.5 times than unfilled neat epoxy, which indicates a significant surge in thermal conductivity at specific filler loading.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-27T09:15:33Z
      DOI: 10.1177/09673911211032487
       
  • An experimental study on quasi-static indentation, low-velocity impact and
           damage behaviors of laminated composites at high temperatures

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      Authors: Akim Djele, Ramazan Karakuzu
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Nowadays, fiber reinforced laminated composites are widely used in many applications due to their high strength/weight ratio. However, these materials are very sensitive to transverse loading. The low-velocity impact test has been widely used by researchers to simulate the transverse loading. However, the low-velocity impact tests are highly toilsome, and this test requires expensive hardware and software systems. To reduce the experimental costs of the low-velocity impact test, it will be more attractive, much simpler, cheaper and more widely available to achieve impact behavior using quasi-static tests. Thus, to compare both tests, in this work the absorbed energy and force-deflection curves obtained by low-velocity impact and quasi-static indentation loading in two different fiber reinforced epoxy composites have been investigated. The Carbon-Kevlar hybrid fabrics and S2 glass fabrics were used as reinforcements. For low-velocity impact tests, a range of energies was used between 20 and 80 J. For quasi-static indentation test, the crosshead speeds were increased gradually from 1 mm/min to 60 mm/min. In addition, tests at 23°C, 40°C, 60°C and 80°C were made to examine the effect of temperature on these tests. As a result of the quasi-static tests performed, the amount of energy required to perforate the samples at a certain test speed is at the same level as the low-velocity impact test. Thus, the required energy amount for the perforation of the materials can be found by performing a quasi-static test at an appropriate speed, rather than the low-velocity impact test.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-26T09:54:25Z
      DOI: 10.1177/09673911211016932
       
  • Novel modification of styrene butadiene rubber/acrylic rubber blends to
           improve mechanical, dynamic mechanical, and swelling behavior for oil
           sealing applications

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      Authors: Ahmed Abdel-Hakim, Soma A el-Mogy, Ahmed I Abou-Kandil
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Blending of rubber is an important route to modify properties of individual elastomeric components in order to obtain optimum chemical, physical, and mechanical properties. In this study, a novel modification of styrene butadiene rubber (SBR) is made by employing acrylic rubber (ACM) to obtain blends of outstanding mechanical, dynamic, and oil resistance properties. In order to achieve those properties, we used a unique vulcanizing system that improves the crosslink density between both polymers and enhances the dynamic mechanical properties as well as its resistance to both motor and break oils. Static mechanical measurements, tensile strength, elongation at break, and hardness are improved together with dynamic mechanical properties investigated using dynamic mechanical analyses. We also proposed a mechanism for the improvement of crosslink density and consequently oil resistance properties. This opens new opportunities for using SBR/ACM blends in oil sealing applications that requires rigorous mechanical and dynamic mechanical properties.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-19T08:12:23Z
      DOI: 10.1177/09673911211031351
       
  • Synthesis and characterization of polyvinyl chloride/wood flour/organoclay
           ternary composites

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      Authors: Chaouki Bendjaouahdou, Khanssa Aidaoui
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polyvinyl chloride/wood flour (WF)/organoclay (OMMT) ternary composites were prepared by melt blending. Chemically treated and untreated pine WF were used as filler, and organically modified montmorillonite or OMMT was added in order to get a potential synergy effect between polyvinyl chloride, untreated wood flour (UWF), or chemically treated WF. The OMMT loading in the composites was 0.5, 1, or 1.5 wt%. The chemically treated and UWF loadings were 1, 5, and 10 wt%. The composite specimens were subjected to mechanical tests (evaluation of tensile strength, elongation at break, and Shore A hardness), thermal stability (Beilstein test), processability characterizations, water resistance absorption, and morphological (optical microscopy) observations. The main results showed that the chemically treated WF were more efficient than the UWF for improving the mechanical and physical properties of polyvinyl chloride. Similar results were reported in the scientific literature. Therefore the chemically treated WF can be a cheap, eco-friendly, and renewable substitute for chalk as a filler which is normally used in the fabrication of Polyvinylchloride based cable insulators.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-13T10:55:28Z
      DOI: 10.1177/09673911211031139
       
  • Morphological and thermal characterization of an immiscible catalyzed
           polymer blends (PC/PET)

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      Authors: O Meziane, AR Bensedira, M Guessoum
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim is to study the reactive compatibilization of two immiscible thermoplastic polyesters, namely polycarbonate (PC) and poly (ethylene terephthalate) (PET), by transesterification reactions through melt compounding. For this, a catalyst, which is hydrated samarium acetylacetonate (Sm(acac)3), is incorporated with concentrations of 0.10, 0.15 and 0.20 phr into the 70PC/30PET mixture.The characterization of the PC/PET blends by differential scanning calorimetry (DSC) revealed that, the transesterification reactions in the absence of catalyst are undetectable or practically impossible; however, by increasing the catalyst concentration, significant variations are noticed on the thermal properties. These modifications, due to the interfacial reactions between the two phases of the system, were also evidenced by variations in morphological properties observed after the study of atomic force microscopy (AFM).
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-09T09:33:19Z
      DOI: 10.1177/09673911211025234
       
  • Fabrication and properties of polyaniline/ramie composite fabric based on
           in situ polymerization

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      Authors: Guizhen Ke, Mofasser Haque Chowdhury, Xinya Jin, Wenbin Li
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polyaniline (PANI) is one of the most important conducting polymer and has been widely used in various fields for its tunable electrical conductivity. In this manuscript, conductive polyaniline/ramie fabrics were developed by in situ polymerization and characterized. The effect of aniline content, polyetherimide (PEI) pretreatment, padding and the color depth (K/S value) on electrical resistivity was analyzed. The result showed that electrical conductivity was increased with the increase of aniline (ANI) contents. PEI pretreatment and padding method improved the conductivity of the fabric significantly. The result of K/S value was reversely consistent with the conductivity. Both scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed that polyaniline particles were successfully deposited on the surface of the ramie fabrics. Thermal degradation (TG) measurement showed that polyaniline (PANI) polymerization decreased the onset decomposition temperature. Mechanical measurement showed that pretreatment process reduced the tensile strength of conductive ramie fabrics by 30%. K/S value in full range showed that the color of PANI/ramie fabric was sensible to pH value. Contact angle (CA) measurement disclosed the conductive PANI/ramie fabric was hydrophobic and this hydrophobicity was stable to the change of pH value. The obtained PANI/ramie fabrics can be used as potential conductive multifunctional textiles.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-05T10:08:27Z
      DOI: 10.1177/09673911211028398
       
  • Preclinical assessment of chitosan–polyvinyl alcohol–graphene oxide
           nanocomposite scaffolds as a wound dressing

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      Authors: Arash Montazeri, Fariba Saeedi, Yaser Bahari, Ahmad Ahmadi Daryakenari
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The present research aimed to examine the biological properties of chitosan (CS)–polyvinyl alcohol (PVA) scaffolds reinforced with graphene oxide (GO) nanosheets, as wound dressings. The scaffolds were characterized by various techniques. The scanning electron microscopy (SEM) and thermogravimetry analyses (TGAs) were used to investigate distribution of the GO within the polymer. The viscoelastic properties were evaluated by dynamic mechanical thermal analysis (DMTA) to examine the quality of a wound dressing. In vitro and in vivo studies were conducted to assess the biocompatibility of the scaffolds as wound dressing. The cell viability and proliferation results indicated that mouse fibroblast cells (L929) could adhere on the 50CS–50PVA/3 wt% GO scaffold. Herewith, the fabricated CS–PVA–GO nanocomposite scaffolds are suggested as promising biomaterials for skin tissue engineering and wound dressing.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-07-05T07:33:07Z
      DOI: 10.1177/09673911211029242
       
  • Cure kinetics and autoclave-pressure dependence on physical and mechanical
           properties of woven carbon/epoxy 8552S/AS4 composite laminates

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      Authors: Abd Baghad, Khalil El Mabrouk, Sébastien Vaudreuil, Khalid Nouneh
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The final mechanical properties of composite laminates are highly dependent on their curing cycles in the autoclave. During this cycle, the temperature, pressure, vacuum, and treatment time will influence the quality of manufactured parts. The void content is considered the most harmful defects in carbon/epoxy laminates since they weaken the matrix-dominated mechanical properties such as interlaminar shear and compressive strengths. In the present work, differential scanning calorimetry is used to characterize the influence of time/temperature on the behavior of the epoxy resin. Then, a series of [0/90/−45/+45]s laminates composites are autoclave-cured under various applied pressures to evaluate their impact on microstructure and mechanical properties. The interlaminar shear modulus, interlaminar shear strength, laminate compressive modulus, and laminate compressive strength at room and operating engine temperature were measured. The correlation between microstructure and mechanical properties was also studied. The mechanical properties of manufactured carbon/epoxy laminates are found to be dependent on pressure and microstructure. These results are explored to establish an optimal autoclave pressure route that would minimize porosity without counterbalancing mechanical properties.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-29T09:17:32Z
      DOI: 10.1177/09673911211028413
       
  • Synthesis of poly (n-butyl acrylate) with tempo by nitroxide mediated
           polymerization method

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      Authors: Amrita Sharma, PP Pande
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      It has been observed that acrylate monomers are very difficult to polymerize with the low cost nitroxide catalyst 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Therefore, costly acyclic nitroxides such as N-tert-butyl-N-(1-diethylphosphono-2,2-dimethyl)-N-oxyl, (SG1), 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) and TIPNO derivatives have to be used for the polymerization of the acrylic acid derivatives. There are very few reports on the use of TEMPO-derivatives toward the polymerization of n-butyl acrylate. Generally different reducing agents viz. glucose, ascorbic acid, hydroxyacetone etc. have been used to destroy excess TEMPO during the polymerization reaction. The acrylate polymerizations fail in the presence of TEMPO due to the strong C–O bond formed between the acrylate chain end and nitroxide. To the best of our knowledge, no literature report is available on the use of TEMPO without reducing agent or high temperature initiators, toward the polymerization of n-butyl acrylate. The present study has been carried out with a view to re-examine the application of low cost nitroxide TEMPO, so that it can be utilized towards the polymerization of acrylate monomers (e.g. n-butyl acrylate). We have been able to polymerize n-butyl acrylate using the nitroxide TEMPO as initiator (via a macroinitiator). In this synthesis, a polystyrene macroinitiator was synthesized in the first step from TEMPO, after this TEMPO end-capped styrene macroinitiator (PSt-TEMPO) is used to polymerize n-butyl acrylate monomer. The amount of macroinitiator taken was varied from 0.05% to 50% by weight of n-butyl acrylate monomer. The polymerization was carried out at 120°C by bulk polymerization method. The experimental findings showed a gradual increase in molecular weight of the polymer formed and decrease in the polydispersity index (PDI) with increase in amount of PSt-TEMPO macroinitiator taken. In all experiments conversion was more than 80%. These results indicate that the polymerization takes place through controlled polymerization process. Effect of different solvents on polymerization has also been investigated. In the following experiments TEMPO capped styrene has been used as macroinitiator leading to the successful synthesis of poly n-Butyl acrylate. It has been found that styrene macroinitiator is highly efficient for the nitroxide mediated polymerization, even in very small concentration for the synthesis of poly n-butyl acrylate. High concentration of macroinitiator results in the formation of block copolymers of polystyrene and poly (n-butyl acrylate) viz. polystyrene-block-poly-(n-butyl acrylate). The use of TEMPO toward controlled polymerization is of much importance, because it is the nitroxide commercially available at the lowest cost.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-24T09:56:23Z
      DOI: 10.1177/09673911211024577
       
  • Effect of fiber hybridization on mechanical, thermal, and water absorption
           behavior of HF/CF/HDPE composites

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      Authors: Prashant Srivastava, Shishir Sinha
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The composite materials are present in nature since the prehistoric era. Applications of fiber-based composite materials are increasing day by day in our society to overcome the raised environmental and economic concerns. Hence, waste fiber can be utilized as the best resource to develop composites.The present study deals with the impact of hybridization on the mechanical, thermal, and water absorption behavior of hair and coir fiber-based hybrid composites. The compression molding technique was used to develop the hybrid composites with fixed fiber content (15 wt.%) and was also varied the relative weight percentage of hair and coir fibers [(100% HF), (75% HF/25% CF), (50% HF/50% CF), (25% HF/75% CF) and (100% CF)] in reinforcing phase with HDPE composites S1, S2, S3, S4, and S5, respectively. The composite S2 was achieved superior mechanical attributes as compared to other hybrid/non-hybrid composites. The composite S2 was improved the tensile strength 5% and 35.2% more in comparison to composites S1 and S5, respectively. The thermal behavior (TGA, DTG, and DTA) was also influenced by the blending ratio of fibers of composites. The 5% and 50% weight losses of composite S2 were observed at higher temperature 343.8°C and 465.8°C as compare to other composites, which showed the thermal stability of composites S2. SEM analysis was used to investigate the strength of the fiber-matrix interface, which was shown a significant connection between mechanical and thermal behaviors. The crystallinity of hybrid and non-hybrid composites was examined by using the X-ray diffraction (XRD) analyzer and composite S2 was achieved 326 × 10−9 m crystal size at 21.053° peak position with wavelength 1.5406 × 10−10 m for Cu. The water absorption test was used to examine the moisture resistivity of composite materials, which was helpful to increase the applications of materials in humid areas.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-23T11:45:40Z
      DOI: 10.1177/09673911211027129
       
  • Cross-sectional microanalysis for tracking the effect of solvent on the
           morphological evaluation of PLA/AgNWs bionanocomposties

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      Authors: Meltem Sezen, Busra Tugba Camic
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The emphasis of biocompatible polymer applications in medical sciences and biotechnology has remarkably increased. Developing new low-cost, low-toxicity and lightweight composite forms of biopolymers has become even more attractive since the addition of new species into polymer matrices assist to improve biomedical activities of such materials to a higher extend. Developments in nanoscience and nanotechnology recently contribute to controlled fabrication and ultraprecise diagnosis of such materials. This study concerns the observation of solution processing effects in the fabrication of porous PLA/AGNWs bionanocomposite coatings using electron and ion processing based serial cross-sectioning and high-resolution imaging. The nanostructuring and characterization were both performed in a focused ion-beam-scanning electron microscope (FIB-SEM) platform. HR-SEM imaging was conducted on-site to track solvent based morphological property alterations of PLA and PLA/AgNWs structures. Simultaneous SEM-EDS analyses revealed the elemental distribution and the chemical composition along the cross-sectioned regions of the samples. Accordingly, it was observed that, in case of acetone dissolved materials, both pristine PLA and PLA/AgNWs samples sustained their foamy structure. When chloroform was used as the solvent, the porosity of the polymer matrices was less and the resulting structure was found to be denser than samples dissolved in acetone with a lower surface area ratio inside the material. This can be attributed to the rapid volatilization of acetone compared to chloroform, and hence the formation of interconnected pore network. For both nanocomposite biopolymers dissolved in acetone and chloroform, silver nanowires were homogeneously distributed throughout PLA matrices.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-23T11:41:21Z
      DOI: 10.1177/09673911211023038
       
  • Effect of electrospinning parameters on production of polyvinyl
           alcohol/polylactic acid nanofiber using a mutual solvent

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      Authors: Reyhaneh Fatahian, Mohammad Mirjalili, Ramin Khajavi, Mohammad Karim Rahimi, Navid Nasirizadeh
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Differences in the properties of poly(vinyl alcohol) (PVA) and poly (lactic acid) (PLA) polymers have attracted much attention today. In this research, the aim is to produce PVA/PLA nanofibers with hydrophilicity and good mechanical properties using a mutual solvent. In this regard, the ability to produce PVA/PLA nanofibers using a mutual solvent was evaluated. The effect of electrospinning parameters on the morphology of nanofibers, hydrophilicity of nanofibers produced by measuring water absorption and contact angle as well as mechanical properties of nanofibers were considered. The results obtained from scanning electron microscopy analyses of the structure of these fibers showed that PVA had the highest viscosity of 5.64 Pa.s and the highest diameter of 260 nm, which decreased the thickness of the nanofibers with increasing PLA. And pure PLA had the lowest mean diameter of 76 nm. In the consideration of the mechanical properties of the prepared nanofibers, it was found that the combination of PLA and PVA nanofibers will lead to overlap the properties of each other and the creation of desirable mechanical properties. Moreover, in the investigation of water absorption and contact angle, it was concluded that the PVA/PLA was fully absorbed in less than 200 seconds and the samples have a contact angle of less than 52°. Finally, it was found that the average diameter of the produced nanofibers was decreased by increasing the voltage and the needle tip to collector distance by considering the PVA/PLA samples with a ratio of 50:50.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-22T09:52:10Z
      DOI: 10.1177/09673911211027126
       
  • Thermomechanical postbuckling of higher order shear deformable
           CNT-reinforced composite plates with elastically restrained unloaded edges
           

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      Authors: Le Thi Nhu Trang, Hoang Van Tung
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Buckling and postbuckling behavior of carbon nanotube (CNT) reinforced thick composite plates resting on elastic foundations and subjected to thermomechanical loads are investigated in this paper. The plates are subjected to uniform uniaxial compression in a thermal environment or the combined action of nondestabilizing preexisting uniaxial compression and uniform temperature rise. CNTs are reinforced into matrix through functionally graded distributions. The properties of constitutive materials are assumed to be temperature dependent and effective properties of CNT-reinforced composite are determined according to an extended rule of mixture. Governing equations are based on a higher order shear deformation theory taking von Kárman nonlinearity, initial geometrical imperfection, elasticity of tangential restraints of unloaded edges and plate-foundation interaction into consideration. Analytical solutions are assumed to satisfy simply supported boundary conditions and Galerkin method is applied to obtain nonlinear load-deflection relations. Numerical analyses are carried out to show the effects of CNT distribution patterns, preexisting loads, initial imperfection, degree of in-plane constraint, and elastic foundations on the nonlinear thermomechanical stability of CNT-reinforced composite plates.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-22T09:48:46Z
      DOI: 10.1177/09673911211025961
       
  • Synthesis and characterization of flame-retardant-wrapped carbon nanotubes
           and its flame retardancy in epoxy nanocomposites

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      Authors: Jiangbo Wang
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      A novel phosphorus-silicon containing flame-retardant DOPO-V-PA was used to wrap carbon nanotubes (CNTs). The results of FTIR, XPS, TEM and TGA measurements exhibited that DOPO-V-PA has been successfully grafted onto the surfaces of CNTs, and the CNTs-DOPO-V-PA was obtained. The CNTs-DOPO-V-PA was subsequently incorporated into epoxy resin (EP) for improving the flame retardancy and dispersion. Compared with pure EP, the addition of 2 wt% CNTs-DOPO-V-PA into the EP matrix could achieve better flame retardancy of EP nanocomposites, such as a 30.5% reduction in peak heat release rate (PHRR) and 8.1% reduction in total heat release (THR). Furthermore, DMTA results clearly indicated that the dispersion for CNTs-DOPO-V-PA in EP matrix was better than pristine CNTs.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-22T09:48:21Z
      DOI: 10.1177/09673911211024582
       
  • Synthesis and characterization of poly(butylene terephthalate)
           copolyesters derived from threitol

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      Authors: N Ittobane, A Martínez de Ilarduya, A Alla, S Muñoz-Guerra
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The synthesis, characterization, and thermal properties of partially renewable poly(butylene terephthalate) copolyesters containing alditol units are described. These copolyesters were obtained by polycondensation in solution from mixtures of 1,4-butanediol and 2,3-di-O-benzyl-L-threitol with terephthaloyl chloride. Copolyesters with weight-average molecular weights oscillating between 4 000 and 12 000 g·mol−1 and dispersities around 1.5 were obtained. All them had a random microstructure and were thermally stable well above 300°C. Copolyesters containing up to 30% of dibenzyl threitol units were found to be crystalline and to adopt the same crystal structure as the parent homopolyester poly(butylene terephthalate). The melting temperature and crystallinity were observed to decrease, and the glass transition temperature to increase, with increasing amounts of alditol units incorporated in the copolyester. Furthermore, the crystallizability was depressed by copolymerization.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-21T10:12:03Z
      DOI: 10.1177/09673911211023298
       
  • Development of fiber-reinforced transparent composites

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      Authors: Robert Meinders, David Murphy, Gregory Taylor, K Chandrashekhara, Thomas Schuman
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, a continuous glass fiber-reinforced composite is manufactured using the vacuum assisted resin transfer molding (VARTM) process. The composite is manufactured from an S-glass fiber acting as reinforcement and an epoxy resin as matrix. Unlike a traditional E-glass fiber reinforcement, S-glass fibers give higher stiffness and provide easier manufacturability due to the value of the refractive index of S-glass lying within the range of refractive indices of the epoxy resin. The epoxy resin is synthesized Epon 826, Epalloy 5200, and hexahydropthalic anhydride and tailored to match refractive indices of the S-glass fibers. After synthesis of the resin, composite panels are manufactured from the synthesized epoxy resin and S-glass fibers with a bi-directional [0°/90°] 8-harness satin weave. VARTM process was utilized to manufacture the composite panels. Composite panels are visually inspected for transparency, and tensile, flexural, and impact testing is performed. Mechanical tests showed consistent results for tensile modulus, tensile strength, flexural modulus, flexural strength, and impact damage resistance.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-21T10:11:13Z
      DOI: 10.1177/09673911211023031
       
  • Effect of fibre content on the mechanical properties of hemp fibre woven
           fabrics/polypropylene composite laminates

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      Authors: Sheedev Antony, Abel Cherouat, Guillaume Montay
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Nowadays natural fibre composites have gained great significance as reinforcements in polymer matrix composites. Composite material based on a polymer matrix reinforced with natural fibres is extensively used in industry due to their biodegradability, recyclability, low density and high specific properties. A study has been carried out here to investigate the fibre volume fraction effect of hemp fibre woven fabrics/PolyPropylene (PP) composite laminates on the tensile properties and impact hammer impact test. Initially, composite sheets were fabricated by the thermal-compression process with desired number of fabric layers to obtain composite laminates with different fibre volume fraction. Uniaxial, shear and biaxial tensile tests were performed and mechanical properties were calculated. Impact hammer test was also carried out to estimate the frequency and damping parameters of stratified composite plates. Scanning Electron Microscope (SEM) analysis was performed to observe the matrix and fibre constituent defects. Hemp fabrics/PP composite laminates exhibits viscoelastic behaviour and as the fibre volume fraction increases, the viscoelastic behaviour decreases to elastic behaviour. Due to this, the tensile strength increases as the fibre content increases. On the other hand, the natural frequency increases and damping ratio decrease as the fibre volume fraction increases.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-18T09:16:10Z
      DOI: 10.1177/09673911211023942
       
  • Mechanical properties and dimensional stability of jute/VER-isocyanate
           hybrid matrix composites

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      Authors: Richa Singh, B Singh, M Gupta, VK Singh
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Some composites of alkali treated jute fibers and vinylester-isocyanate/urethane hybrid resin were fabricated. The mechanical, thermo-mechanical, fractographic and aging behavior of these composites were studied and compared with the parent vinylester resin (VER) matrix composites. Using hybrid resin matrix, the impact strength of jute composites was increased by ∼20% over the VER matrix composites. It was, however, accompanied by the marginal improvement in their tensile and flexural properties. Dynamic mechanical analysis showed increased storage modulus and broadened tan δ peak when VER-isocyanate hybrid resin was used as a matrix material compared with the parent VER matrix in jute composites showing its superior stiffness and flexibility. In humid environment, a decrease in the weight gain and swelling thickness was observed for VER-isocyanate hybrid matrix jute composites after 60 days exposure when compared with the parent VER matrix composites. Under accelerated water aging, the drop of 12–24% in the tensile strength was noticed for VER-isocyanate hybrid matrix jute composites as compared to ∼29% for VER matrix composites. The changes in the mechanical response of all composites can be well co-related with their fractographic evidences existed onto the tensile fracture surfaces in both dry and wet conditions.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-18T09:03:44Z
      DOI: 10.1177/09673911211016648
       
  • Flax fiber reinforced polylactic acid composites for non-structural
           engineering applications: Effect of molding temperature and fiber volume
           fraction on its mechanical properties

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      Authors: Jai Inder Preet Singh, Sehijpal Singh, Vikas Dhawan, Piyush Gulati
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Owing to its biodegradability, durability, low cost and potential material to replace existing commercial products in the field of engineering applications, nowadays there is a lot of interest in the field of green composites. It is formed by a mixture of biodegradable polymers and natural fibers and has a potential to replace synthetic polymer based composites. In this research work flax fibers are used as reinforcement and Poly-lactic acid (PLA) as matrix material for the development of Flax/PLA composites. The effects of processing parameters such as fiber volume fraction ranging from 25% to 50% and molding temperature ranging from 160°C to 180°C on mechanical properties of flax/PLA composites were investigated. It is concluded from the results that maximum tensile and flexural strength are recorded at 35% fiber volume fraction of flax/PLA composites developed at 170°C molding temperature. SEM analysis validated the findings obtained from the mechanical characterization.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-17T09:37:34Z
      DOI: 10.1177/09673911211025159
       
  • A multiscale homogenization procedure to predict the elasto-viscoplastic
           behavior of polymer-based nanocomposites

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      Authors: Mohammad Hassan Shojaeefard, Abolfazl Khalkhali, Sharif Khakshournia
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      It has been demonstrated that adding a few percent of nanoscale reinforcements, leads to remarkable improvement in mechanical properties of the polymers such as stiffness, damping, and energy absorption. These lightweight materials are attractive substitutes for the heavy metallic structural parts in the automotive, military, aerospace and many other industries. However, due to complexity of these multiphase materials, accurate modeling of their behavior in real loading cases is still ambiguous. The impact simulation is a vital step in design procedure of a vehicle, where a strain rate-dependent model of its components is required. In this paper, an elasto-viscoplastic modeling procedure of the polymer-based nanocomposites, assuming the elastic behavior of the nano-phase is presented; whereas the polymeric matrix deformation is dependent to the loading rate and is characterized by the method of Genetic algorithm optimization-based fitting to the experimental observations. By introducing a modified Halpin-Tsai method, the nanocomposite is then modeled as a homogenized material where the modification algorithm is the main challenge. A combination of approaches including parametric analysis, central composite design of experiments and response surface method is proposed to modify the tangent modulus of the polymeric matrix to be passed as the input to the Halpin-Tsai equations. Finally, the procedure is implemented to a set of epoxy-GNP nanocomposites under unidirectional compressive loads with different rates and the stress-strain curves are predicted with a decent precision.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-17T09:36:51Z
      DOI: 10.1177/09673911211023305
       
  • Fabrication and characterization of polyaniline functionalized graphene
           nanosheets (GNSs)/polydimethylsiloxane (PDMS) nanocomposite films

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      Authors: Yasin Altin, Omer Faruk Unsal, Ayse Celik Bedeloglu
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, graphene nanosheets (GNSs)/poly(dimethylsiloxane) (PDMS) nanocomposites and the novel polyaniline (PANI)-functionalized graphene nanosheets (GNSs)/poly(dimethylsiloxane) (PDMS) nanocomposites were fabricated successfully. GNSs and PANI-functionalized GNSs were dispersed in PDMS matrix at different nanofiller concentration and nanocomposites were prepared via solution casting method. PANI functionalization were performed by in-situ polymerization of aniline in the presence of GNSs and was used in order to be dispersed homogenously and efficiently in the PDMS matrix. Besides graphene layers were also isolated to hinder aggregation in the polymeric matrix. The effect of PANI functionalization of GNSs and filler concentration on dielectric, electrical and mechanical properties of nanocomposite films were investigated. According to dielectric measurements, the dielectric constant of polymer nanocomposites highly dependant on frequency, so dielectric constant was characterized in a wide frequency range (1 Hz–10 MHz) at room temperature, in this study. The dielectric constant of PDMS nanocomposites containing 1.50% GNSs and 1.50% PANI-GNSs increased by 111 times and 24 times, at 1 Hz, compared to pure PDMS, respectively. Besides, electrical conductivity increased 6868 and 1474 times with the addition of GNSs and PANI-GNSs, respectively. Optimized GNSs/PDMS and PANI-functionalized GNSs/PDMS nanocomposites can be candidate for soft actuators to be used in artificial muscle applications, in the future.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-15T09:59:27Z
      DOI: 10.1177/09673911211023941
       
  • In situ suspension polymerization of vinyl chloride/3-(trimethoxysilyl)
           propyl methacrylate (MPTMS)-intercalated Mg-Al-hydroxide layered double
           hydroxide: I. Grain properties

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      Authors: Reza Darvishi, Mohammad Javad Bijhanmanesh, Ghasem Payam
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Suspension polymerization of vinyl chloride (VCM) was carried out in the presence of particle of both pristine Mg-Al layered double hydroxide (LDH) and LDH intercalated by 3-(trimethoxysilyl) propyl methacrylate (MPTMS-LDH) in a pilot-scale reactor. The experiments were conducted at different concentrations of each type of the particles (0, 1, 3, 5, 7 wt. % of VCM). The pure LDH and MPTMS-intercalated LDHs were used as co-monomer for fabrication of LDH or MPTMS-LDH/PVC nanocomposites; the particles were directly pre-dispersed in monomer phase before dispersing in the continuous aqueous phase and starting the suspension polymerization. The basal spacing obtained from the X-ray powder diffraction (XRD) showed that the reaction between VCM and MPTMS-LDH was effective, with a further intercalation of PVC chains in the interlayer space. The molecular characterization showed that the polydispersity index (PDI) and molecular weight of the poly (vinyl chloride) (PVC) resin do not change in the presence of the pristine LDH. The MPTMS-LDH, however, decrease the molecular weight and increase the PDI of PVC resin. Also, from the morphological point of view, scanning electron microscopy (SEM) showed that PVC grains produced with high particles content had a smoother surface with more regular shape. Moreover the incorporation of nanoparticles in the VCM suspension polymerization, made particles with a narrower size distribution. The LDH results in the formation of smaller primary particles with higher internal porosity whereas, the larger primary particles with lower internal porosity in the presence of modified particles was observed.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-15T09:57:27Z
      DOI: 10.1177/09673911211023940
       
  • Assessment of drilling-induced delamination and tool wear in carbon fibre
           reinforced laminates

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      Authors: SA Arhamnamazi, F Aymerich, P Buonadonna, M El Mehtedi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      A highly accurate X-ray damage characterization technique was used in this study to investigate the correlation between hole damage, tool wear and thrust force in drilling of carbon fibre reinforced laminates. Woven carbon/epoxy panels were drilled with a twist tool for 592 holes and the internal damage induced by drilling was investigated by high-resolution penetrant-enhanced X-radiography for comparison with damage evaluated by visual inspection. The study shows that the dominant damage mode induced by drilling is delamination and that tool wear has a significant effect on the size of the delaminated area. The analyses also show that the delaminated areas estimated by visual inspection are much smaller than those identified by X-radiography. This finding indicates that visual observation techniques may provide dangerously unconservative indications and should be used in association with more reliable damage evaluation methods to assess the hole quality of drilled carbon fibre reinforced composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-11T09:10:57Z
      DOI: 10.1177/09673911211023057
       
  • Mixed and single gas permeation performance analysis of amino-modified ZIF
           based mixed matrix membrane

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      Authors: Zarrar Salahuddin, Sarah Farrukh, Arshad Hussain, Tayyaba Noor, Witold Kwapinski
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Dense and translucent CA/PEG 1000/ZIF membranes were synthesized in acetone, utilizing solution casting. Membrane characterization was carried out using FT-IR, SEM and tensile testing. SEM proved presence of dense membranes and increase in the filler amount may have formed voids, raising the permeability of both gases. Single and mixed gas (CO2/CH4) permeation testing showed an increased permeability, on addition of more filler, which is probably due to formation of nano-gaps. A maximum selectivity of 39.49 and 34.86 for single and mixed gases respectively, and maximum permeabilities of 49.7685 and 1.41 barrers were observed. Tensile testing showed that strength peaked then decreased on increased loading, due to agglomeration on adding more ZIF, which introduced defects in structure. To conclude, selectivity of higher loaded membranes is favourable whereas tensile strength of lower loaded membrane is superior, but we have a trade-off between selectivity and tensile strength, so a higher-loaded membrane is most suitable.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-10T10:00:59Z
      DOI: 10.1177/09673911211023303
       
  • Effect of surface modification on mechanical properties of filature silk
           waste and nanoclay filler-based polymer matrix composite

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      Authors: Rahul Nair, Abhishek Bhattacharya, Papiya Bhowmik, Ravi Kant
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Natural fibers have been attracting researchers and engineers as an alternative reinforcement of synthetic fibers in polymer composites due to their low cost, availability from natural resources, satisfactory high modulus and tensile strength, and biodegradability. Filature silk waste (FSW) is the remnant part of the cocoons which is produced during the silk forming process. The current study focuses on the comparison of tensile properties between untreated filature silk waste reinforced epoxy-based composite (UTFSWREC), 2 wt% alkali-treated filature silk waste reinforced epoxy-based composites (TFSWREC) and 2 wt% alkali-treated filature silk waste reinforced epoxy nanocomposites (TFSWRENC). The tensile properties showed that Young’s modulus of composites increases with surface modification of fiber and further enhances with nanoclay filler. TFSWREC and TFSWRENC displayed a higher tensile modulus than UTFSWREC. Scanning Electron Microscopy (SEM) showed the removal of the sericin layer from the surface of fiber, which resulted in the separation of fibrils and further resulted in the enhancement of the mechanical properties. FTIR analysis confirmed that intermolecular bonding improves with the chemical treatment and further refined with nanoclay filler addition.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-10T10:00:10Z
      DOI: 10.1177/09673911211023043
       
  • Characterization of the dynamic mechanical properties of sisal fiber
           reinforced PET composites; Effect of fiber loading and fiber surface
           modification

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      Authors: Adane Dagnaw Gudayu, Leif Steuernagel, Dieter Meiners, Rotich Gideon
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Dynamic mechanical analysis (DMA) is an essential procedure for characterizing the performance of composites and effectively simulate with the real-world applications. This research work aims to characterize the dynamic mechanical (DM) properties of sisal fiber reinforced polyethylene terephthalate (PET) composites as a factor of fiber content and fiber surface modification. The effect of elevated processing temperature (>260°C) on the thermal degradation of sisal fibers is also analyzed. To study the effect of sisal fiber loading, PET composite specimens; one with 25% by weight fraction of raw sisal fiber (w/w), abbreviated as 25% RSC and the other with 40% by weight fraction (w/w) of raw sisal fiber, hereafter abbreviated as 40% RSC, were prepared by injection molding. Similarly, to analyze the impact of fiber surface modifications, PET composite samples containing 40% by weight fraction (w/w) of alkali-treated sisal, hereafter abbreviated as (40% Al-SC), and 40% by weight fraction (w/w) of a combined alkali/acetylation-treated sisal, hereafter abbreviated as (40% Al-ASC), were prepared. It was found that the fiber volume fraction and fiber surface modifications affected the DM properties of the produced composites. The improved storage module and glass transition temperature (Tg) with minimized damping has been demonstrated by increasing fiber content. With the same 40% fiber content, the composites produced from modified fibers enhanced the storage modulus and Tg values. However, with increasing temperature, the storage modulus decreased, the loss modulus increased, and the damping factor increased with composites containing higher fiber content and surface modified fibers. This indicates the low thermal stability of the sisal fiber and the interface damage at elevated temperatures.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-10T09:59:25Z
      DOI: 10.1177/09673911211023032
       
  • Nanocomposites based on biocompatible polymers and graphene oxide for
           antibacterial coatings

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      Authors: Fika Fauzi, Muhammad Miqdam Musawwa, Habibi Hidayat, Ahmad Kusumaatmaja, Wipsar Sunu Brams Dwandaru
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Recently, antibacterial coatings based on graphene oxide (GO) nanocomposites have attracted many studies around the world. The use of polymers as the matrices of GO nanofillers in the nanocomposites has been explored to produce efficient coatings against bacteria. One of the most prospective applications is the incorporation of GO into biocompatible polymers, which can produce antibacterial coatings. Here, recent progresses on the antibacterial coatings of nanocomposites based on biocompatible polymers and GO are reviewed. The effect of GO filler concentrations, biocide materials, and biocompatibility are discussed to find the most efficient antibacterial activity and biocompatibility of nanocomposites. Among biocompatible polymers, chitosan (Cs), poly vinyl alcohol (PVA), and poly lactic acid (PLA) are the most popular matrices used for the nanocomposites. This review also elaborates challenges in the use of other biocompatible polymers. Future works on biocompatible antibacterial coatings should be conducted by considering the concentration of GO nanofillers or adding other materials such as essential oils to suppress the toxicity toward functional cells.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-07T09:43:07Z
      DOI: 10.1177/09673911211020601
       
  • Thermal behavior of N-Methylaniline modified phenolic friction composites

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      Authors: Yusubov Fikrat Fakhraddin
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This article discusses observations on thermal stability, decomposition properties and degradation of organic components of friction composite materials fabricated by powder metallurgy techniques. N-Methylaniline modified phenolic resin used as a binder material in the preparation of composite materials. Thermogravimetry method was used to study the thermal properties of the samples. The experiments were performed on a TGA Q50 (TA Instrument) in an oxygen atmosphere. In order to better assess the thermal characteristics of the composites, the analyses were carried out by separating thermographs into three parts according to the degradation mechanism. The obtained results helped to assess the thermal stability of the friction materials. The degradation of phenolic resin was observed in the temperature range of 312–362°C. It was found that barite and copper-graphite particles improve the thermal characteristics of the samples.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-02T09:41:44Z
      DOI: 10.1177/09673911211020718
       
  • Synthetic glass and jute fabric reinforced soy-based biocomposites:
           Development and characterization

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      Authors: Ajaya Kumar Behera, Chirasmayee Mohanty, Nigamananda Das
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this work, both glass fabric and jute fabric reinforced nanoclay modified soy matrix-based composites were developed and characterized. Glass fabric (60 wt.%) reinforced composite showed maximum tensile strength of 70.2 MPa and thermal stability up to 202°C, which are 82.8% and 12.2% higher than those observed with corresponding jute composite. Water absorption and contact angle values of glass-soy specimens were tested, and found composites are water stable. Biodegradation study of composites under soil burial condition revealed that glass-soy composite with 40 wt.% glass fabric lost maximum 32.6% of its original weight after 60 days of degradation. The developed glass fabric-soy hybrid composites with reasonable mechanical, thermal, and hydrolytic stability can be used in different sectors as an alternative to the nondegradable thermoplastic reinforced glass fabric composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-06-01T09:37:36Z
      DOI: 10.1177/09673911211020609
       
  • Effects of natural hard shell particles on physical, chemical, mechanical
           and thermal properties of composites

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      Authors: Yahya Hışman Çelik, Kadir Serdar Çelik, Erol Kilickap
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Shelled herbal foods are widely consumed. The evaluation of the shells of these foods is important due to their features such as low cost, ease of recycling and environmental friendliness. In this study, hazelnut shell (HS), pistachio shell (PS), and apricot kernel shell (AKS) were brought to powder particles by grinding to dimensions of 300–425 µm. Some of the powder particles were converted into ash at 900°C. The amounts of cellulose, ash, humidity, and metal in these particles via chemical analyses were determined, while their structural properties via X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) analyses. Composite materials were produced by adding 15 wt.% to the polyester matrix material from these powder particles and ashes. Compression strength, hardness, specific weight, and thermal conductivity of these composites were analyzed. The lowest and highest humidity, ash, cellulose, hemicellulose, and lignin ratios in powders showed differences depending on the type of powders. The amount of Sn and K in the HS, PS, and AKS powders were close to each other, while the amount of Ca, Na, Mg, Fe, Mn, Cu, Zn and Si was higher in AKS powder. The reinforcement adding to the polyester increased the compression strength, hardness, specific weight and thermal conductivity properties.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-31T09:13:09Z
      DOI: 10.1177/09673911211020717
       
  • A comparative study of mechanical and machining performance of polymer
           hybrid and carbon fiber epoxy composite materials

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      Authors: A Tamer Erturk, Eser Yarar, Fahri Vatansever, Alp Eren Sahin, Mert Kilinçel, Yakup Okan Alpay
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Fiber-reinforced plastics are known as advanced composite materials thanks to their high strength and lightweight features. Carbon fiber reinforced polymers (CFRPs) are one of the high-performance and high-cost fiber-reinforced polymer (FRPs) materials. They are used in several high-performance engineering applications such as motorsports, marine, aviation, energy and defense industry. The cost of carbon fiber is higher compared to many other materials, more competitive and cost-effective productions will spur the demand for composite parts exponentially. Thus, hybrid laminate composite containing carbon and glass fiber materials were manufactured as an alternative for CFRP materials. Because using glass fiber prepreg instead of carbon fiber prepreg will lead the material to become cheaper. However, machining of the FRP materials is still an important issue. For this reason, the present study is focused on the mechanical and machining performance of the polymer hybrid and carbon fiber epoxy composites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-31T09:12:10Z
      DOI: 10.1177/09673911211020620
       
  • Preparation of multi-walled carbon nanotubes/high density polyethylene
           composites with enhanced properties by using a master batch method

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      Authors: Fu-An He, Li-Ming Zhang
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Multi-walled carbon nanotubes (MWCNTs)/high density polyethylene (HDPE) composites were prepared by a masterbatch method (mPEC) in which a commercial HDPE was blended with a MWCNTs/HDPE masterbatch obtained from in situ polymerization. Owing to the interfacial interaction, a 13 cm−1 up-shift of the G band for the MWCNTs was observed in the Raman spectrum of the MWCNTs/HDPE masterbatch and the homogeneous distribution of MWCNTs in the mPEC was realized. Compared to the pure HDPE and the MWCNTs/HDPE composites prepared by a direct melt-blending method (dPEC), the mPEC had better electrical, mechanical and rheological properties, suggesting that the in situ polymerized HDPE covering on the MWCNTs surfaces played an important role in the reinforcing effects as an interfacial modifier. The tensile yield strength and the Young’s modulus of the mPEC containing 3 wt% MWCNTs (mPEC3), and the flexural strength and the flexural modulus of the mPEC containing 1 wt% MWCNTs were improved by 38.3%, 41.7%, 24.4%, and 42.9%, respectively, compared to those of the pure HDPE. For, the electrical resistivity of mPEC3 was decreased by about three orders of magnitude relative to that of the pure HDPE. The η* , G′, and G″ of the mPEC were obviously higher than those of pure HDPE. Moreover, the polyethylene-modified MWCNTs obtained from in situ polymerization could facilitate the crystallization of the HDPE macromolecular chains more effectively compared to the unmodified MWCNTs.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-24T09:59:18Z
      DOI: 10.1177/09673911211017855
       
  • Non-wettable antibacterial thin film: PS/Aloe vera and PS/Acalypha indica

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      Authors: O Seifunnisha, R Swathi, J Shanthi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The water and liquid repelling materials due to their low surface energy and specific nanometer and micrometer scale roughness have particular interest due to the great variety of potential applications ranging from self-cleaning surfaces to microfluidic devices. Natural plant-based polymer hydrophobic coatings have several engineering and biomedical applications. In this study, natural plants such as Aloe vera and Acalypha indica were used for preparation of polystyrene hydrophobic film by the dip-coating method. The effects of Aloe vera and Acalypha indica extract on the morphological, structural, optical and antibacterial properties of as-prepared polystyrene thin films were studied. FTIR spectra were carried out to ascertain the presence of functional groups in the prepared polymeric film. Contact angle measurement showed that the PS/Aloe vera has higher anti-wetting property (CA = 112°) compared to PS/Acalypha indica (CA = 104°), which could be confirmed by the surface morphology analysis. Furthermore, the effective antibacterial activity against Klebsiella pneumoniae and Staphylococcus aureus was compared by agar-well diffusion method. The observed result reports, PS with Aloe vera film exhibit higher hydrophobic with antibacterial activity compared to PS with Acalypha indica film. In addition, the PS/Aloe vera coated cotton maintained their repellent properties against various liquids for 10 h, while PS/Acalypha indica coated cotton exhibit anti-wetting property for 4 h. These findings open up new avenues for the preparation of hydrophobic film for various biomedical applications.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-17T10:13:49Z
      DOI: 10.1177/09673911211017869
       
  • The preparation of modified polyamide clay nanocomposite/recycled maleic
           anhydride polyamide 6 and blending with low density polyethylene for film
           blowing application

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      Authors: Wei-Hua Yao
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Generally, polyamide cannot be used as film blowing material because of its unsuitable properties. In this study, polyamide 6 clay nanocomposite (cPA) and styrene maleic anhydride copolymer (SMA) were mixed in various ratios for the preparation of modified polyamide 6 clay nanocomposite SxcPAy resins by reactive extrusion. The S1cPA14 resin was blended with recycled maleic anhydride polyamide (rPA) to form the (S1cPA14)x rPAy resins. Finally, they were mixed with LDPE in 1:9 ratio to afford (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins, respectively, followed by film blowing and the analyses of the physicochemical properties of resins. The FTIR spectrum illustrated that the C=O symmetric and asymmetric absorption fingerprint peaks in the anhydride (-OC-O-CO-) group of SMA disappeared and the new characteristic absorption peak of-CO-N-CO- of imides was observed. The anhydride functional group of SMA underwent reactive extrusion with the terminal amino group of cPA to generate the imides structure. The thermal properties showed that the glass transition temperature and crystallinity of SxcPAy and (S1cPA14)x rPAy resins increased with increasing SMA and S1cPA14 contents. The Tg (85.4.0°C) of (S1cPA14)12 rPA1 resin were enhanced significantly, with 30°C higher than cPA. In terms of tensile mechanical properties, S1cPA14 test pieces demonstrated the highest Young’s modulus and tensile strength. After mixing with LDPE, the tensile mechanical properties of (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins and films were both higher than that of LDPE. ((S1cPA14)12 rPA1)1LDPE9 film shown the best tensile properties and barrier performance compared with other films due to the optimal rPA content could assisted SMA as a better compatibilizer to improve the dispersion and compatibility of cPA in HDPE. It was worth noting that (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins were formed by film blowing at the processing temperature of 140°C followed by successful preparation of the film.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-17T10:00:49Z
      DOI: 10.1177/09673911211015000
       
  • Processing method, properties and application of functionally graded
           

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      Authors: LM Amirova, KA Andrianova, LR Amirova
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, the method of manufacturing of functionally graded polymer materials based on the mixtures of poorly compatible epoxy resins is suggested. A novel processing method allowing to control the filler distribution across the section of graded materials depending on the operating conditions was developed. The essence of the method is self-settling of the blend consisting of two liquid epoxy resins with different viscosities and densities. Depending on mixing and injecting order the functional additive having antifriction, anti-adhesive or heat-protective properties can be distributed either homogenously or nonuniformly. In the latter case after curing the functionally graded material can be produced. Based on the formulations of poorly compatible phenol novolac epoxy resin NPPN-638 and active diluent triglycidyl phosphate (TGP), new functionally graded polymer materials with continuous change of composition and properties were developed. The functional additive (graphite, glass microspheres, polytetrafluoroethylene powder) concentrates in the top layer of the self-settled epoxy mixture while the bottom layer is enriched by TGP which possess advantaged adhesion to various substrates. As a result, antifriction, anti-adhesive, heat-protective and intumescent flame retardant coatings with improved performance were obtained.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-11T09:45:53Z
      DOI: 10.1177/09673911211014763
       
  • The effect of nanoparticle additive on surface milling in glass fiber
           reinforced composite structures

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      Authors: Ferhat Ceritbinmez, Ahmet Yapici, Erdoğan Kanca
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, the effect of adding nanosize additive to glass fiber reinforced composite plates on mechanical properties and surface milling was investigated. In the light of the investigations, with the addition of MWCNTs additive in the composite production, the strength of the material has been changed and the more durable composite materials have been obtained. Slots were opened with different cutting speed and feed rate parameters to the composite layers. Surface roughness of the composite layers and slot size were examined and also abrasions of cutting tools used in cutting process were determined. It was observed that the addition of nanoparticles to the laminated glass fiber composite materials played an effective role in the strength of the material and caused cutting tool wear.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-05T10:02:01Z
      DOI: 10.1177/09673911211014172
       
  • Plasticizer effect on dielectric properties of poly(methyl
           methacrylate)/titanium dioxide composites

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      Authors: Ufuk Abaci, H Yuksel Guney, Mesut Yilmazoglu
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The effect of plasticizer on dielectric properties of poly(methyl methacrylate) (PMMA)/titanium dioxide (TiO2) composites was investigated. Propylene carbonate (PC) was used as plasticizer in the samples which were prepared with the conventional solvent casting technique. Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM-EDX) and Differential scanning calorimetry (DSC) analyses and LCR Meter measurements (performed between 300 K and 400 K), were conducted to examine the properties of the composites. With the addition of plasticizer, the thermal properties have changed and the dielectric constant of the composite has increased significantly. The glass transition temperature of pure PMMA measured 121.7°C and this value did not change significantly with the addition of TiO2, however, 112°C was measured in the sample with the addition 4 ml of PC. While the dielectric constant of pure PMMA was 3.64, the ε′ value increased to 5.66 with the addition of TiO2 and reached 12.6 with the addition of 4 ml PC. These changes have been attributed to increase in amorphous ratio that facilitates polymer dipolar and segmental mobility.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-05T10:00:39Z
      DOI: 10.1177/09673911211014757
       
  • Effect of hybrid thermal cycling and shock on flexural properties of
           nanoclay/glass/epoxy nanocomposites

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      Authors: A Bayat, M Damircheli, M Esmkhani
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In present research, the flexural properties of glass/epoxy composites reinforced by nanoclay particles (3, 5 and 7 wt.%) under various hybrid thermal cycling and shock loadings (15 and 30 thermal cycles at immediate −70°C and +100°C temperatures) have been investigated. It was found that the flexural strength of 5 wt.% nanoclay/glass/epoxy nanocomposites under 15 and 30 hybrid thermal loadings was enhanced by 19.35% and 20.78%, respectively. Also, after 15 hybrid thermal loadings, the flexural stiffness of 5 wt.% clay/glass/epoxy nanocomposites increased by 9.30% compared to static conditions. More importantly, after 30 hybrid thermal loadings, by adding more filler contents, the flexural stiffness was increased. For instance, at 7 wt.% clay/glass/epoxy nanocomposites, the flexural stiffness enhanced 17.97% compared to neat composite. FESEM morphology images confirmed that presence of optimum filler contents changed the composites inherent properties. Therefore, the outcome of this research can show various remarkable advantages for researchers to apply nanoclay as nanofillers to reinforce composites structures under hybrid thermal cycling and shock applications.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-05T09:59:49Z
      DOI: 10.1177/09673911211013229
       
  • Green composites and their contribution toward sustainability: A review

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      Authors: Edgar Vázquez-Núñez, Andrea M Avecilla-Ramírez, Berenice Vergara-Porras, María del Rocío López-Cuellar
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The current world environment scenario demands new and more eco-friendly solutions to global problems that cover the demands for materials. This sector has included green polymer-based composites and natural reinforcers from origins of renewable sources, these Green Composites (GC), natural-fiber-reinforced bio-composites in which the matrix is a bio-based polymer, have shown attractive characteristics. Biodegradability is one of the most important attributes for these new “green” materials, in that this characteristic allows for their introduction into the world market as an environmental solution. The manufacturing processes for obtaining these materials have observed important improvements because each raw material exhibits different properties and characteristics and their eco-friendly character has facilitated its incorporation into diverse sectors, such as construction, automotive, packaging, and medicine, among others. At present, this segment represents an important income for some economies, especially those where these resources are available, enhancing the creation of green economies, strengthening the world’s efforts toward sustainability.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-05T09:52:38Z
      DOI: 10.1177/09673911211009372
       
  • An insight into thermal stability and decomposition kinetics of
           polybenzoxazine plasma treated graphene nanocomposites

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      Authors: Milad Karbalaei-Bagher, Zahed Ahmadi, Hossein Nazockdast
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This research was targeted to investigate the effect of oxygen plasma treated graphene nanosheets (tGNSs) on the thermal stability of benzoxazine resin and to have a further and deeper mechanistic understanding of thermal decomposition kinetics of such nanocomposites in 0.5, 1 and 3 wt% of tGNS. The samples were prepared as reported in our previous study. The quality of dispersion of tGNSs within benzoxazine was investigated by X-Ray diffraction (XRD) and scanning electron microscopy (SEM) technique. Also, to ensure the complete curing of samples the differential scanning calorimetry (DSC) analysis was performed. Using thermogravimetric analysis (TGA), it was found that the addition of tGNS improved the char yield and thermal stability parameter of benzoxazine nanocomposites and this improvement was more prominent at 1% and higher amount of nanoparticles. Moreover, the first stage of thermal degradation kinetic of benzoxazine was disappeared above 1 wt% of tGNS. The samples were kinetically analyzed through Kissinger, Flynn-Wall-Ozawa and Friedman and Coats-Redfern method. It was revealed that the overall activation energy was enhanced from 168 to 224 kJ mol−1 and 275 to 420 kJ mol−1 for the second and third stage of degradation using 1 and 3 wt% of tGNS.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-05T09:51:58Z
      DOI: 10.1177/09673911211005341
       
  • A study on the mechanical properties of graphene oxide/epoxy
           nanocomposites

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      Authors: Rahim Eqra, Mohammad Hadi Moghim, Navid Eqra
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aims of this research are to elucidate the role of graphene oxide on the mechanical properties of epoxy and also to obtain an equation for the modeling of its behavior. Accordingly, graphene oxide/epoxy nanocomposite samples are fabricated using the solution casting method. Tensile, flexural, SEM and FTIR tests are conducted on epoxy and the nanocomposite samples afterwards. The obtained results show that the tensile strength of epoxy improves even at low contents of graphene oxide such that 0.3 wt.% of GO yields an improvement of approximately 11.5%. The flexural strength of epoxy is also enhanced by 5.8% with 0.5 wt.% GO. Then, it decreases due to the agglomeration with increasing the GO content. In order to predict the tensile strength of GO/epoxy nanocomposites, a modified Halpin–Tsai equation is obtained with a new introduced correction factor as K = 39.5Vf 1.135exp(2.9−1644.6Vf). The obtained equation is in good agreement with the experimental data.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-05-03T09:51:59Z
      DOI: 10.1177/09673911211011150
       
  • Electrochemical and thermal properties of polymer-layered silicate
           nanocomposites for energy storage applications

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      Authors: A.K. Nath, Bhaswati Sarma
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The present work gives an outline of electrochemical and thermal properties of single ion conducting polymer-layered silicate nanocomposites. High resolution transmission electron microscopy and X-ray diffraction studies prove the intercalation of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) inside the interlayer galleries of montmorillonite (MMT) silicate. Scanning electron microscopy reveals porosity increases with increasing MMT concentration. Room temperature ionic conductivity of 1.2 × 10−5 S cm−1 has been obtained. Electrochemical stability increases with increasing MMT concentration attaining the highest value of 4.2 V at 20 wt.% of MMT. Thermal properties substantiate decomposition temperature in the range of 300–374°C for the nanocomposites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-29T07:33:51Z
      DOI: 10.1177/09673911211012809
       
  • Utilization of tyre rubber hybrid with ceramic and wood for impact energy
           absorption application

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      Authors: M Sermaraj, K Ramanathan, A Athijayamani
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The used tyre rubber, scrap ceramic tiles and wood dust are largely dumped into landfills, which create environmental pollution to the surrounding. The recycling of tyre rubber is very limited, but it has good property to absorb the impact energy. Hence, these materials are used to prepare the composite in the present work. Composite materials were prepared by the resin transfer moulding method with different weight percentage of particles. The tensile, flexural and impact strength of composite specimens were compared with other combination of composites and also with the neat resin sample specimen. The tensile and flexural strength of composites were decreased with the addition of the rubber. But, the rubber particle with the ceramic in the resin matrix increases the impact strength of composite by 45.91% when compared with the neat resin sample. The addition of rubber enhances the impact strength of composite materials with all the combination of particles. The better distribution and good interfacial adhesion of particles with a resin matrix along the fractured surface were observed by the scanning electron microscope. And also, the nature of failure was identified by morphological studies.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-27T08:01:39Z
      DOI: 10.1177/09673911211008019
       
  • The effect of different mixing methods on morphology and mechanical
           properties of PP/EPDM/talc blend

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      Authors: Hamid Yazdani, Nayereh Sadat Mousavi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      To overcome the low modulus and low maximum service temperature of polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) blends, incorporation of talc into blend have been considered. In this study, the effect of various mixing methods of morphological behavior and mechanical properties of PP/EPDM/talc compound were investigated. Samples were prepared by different methods in internal mixer and co-rotating twin-screw extruder. It was found, the tensile properties were not affected by applying different mixing methods.The highest impact resistance was related to sample which had pre-blending on two roll mills and finally mixed in the internal mixer. Scanning electron microscopy (SEM) micrographs showed that the rubber dispersed morphology for all samples and the finest morphology was related to sample with the highest impact resistance. Because of pre-blending of EPDM/talc on two roll mills, this sample showed the best dispersion and distribution of talc.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-26T07:53:50Z
      DOI: 10.1177/09673911211012821
       
  • Melt rheological behaviour of high-density polyethylene/montmorillonite
           nanocomposites

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      Authors: Vishwa Pratap Singh, Ravi Kumar, Ashwith, Priyanka Singh, Satyajit Samanta, Saikat Banerjee
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The present study explains the preparation of high-density polyethylene (HDPE)-based nanocomposites containing different amounts of montmorillonite (MMT) nanoclay (1–10 wt%). These nanocomposites were obtained by melt blending in a co-rotating twin screw extruder in absence and presence of a compatibiliser (HDPE-g-MA). The melt rheological behaviour of HDPE/MMT nanocomposites has been investigated by using capillary rheometer at 190°C, 200°C and 210°C over the shear rate range of 50–1000 s−1. The melt viscosity of HDPE increased marginally at 10 wt% filler loading while addition of compatibiliser to HDPE/MMT composites did not show any significant effect on viscosity. All nanocomposites showed shear thinning and non-Newtonian flow behaviour. The power law index reduced with increase in MMT concentration and increased with increase in temperature while opposite trend was observed for the consistency index. The activation energy was highest for the nanocomposites containing 10 wt% MMT and decreased upon addition of coupling agent.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-23T07:32:45Z
      DOI: 10.1177/09673911211011828
       
  • TiO2 antifouling coating based on epoxy-modified tung oil waterborne resin

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      Authors: Hailiang Hu, Minmin Chen, Mengye Cao
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The eco-friendly functionalized TiO2/polymer antifouling (AF) coating was successfully synthesized by dispersing TiO2 nanoparticles in waterborne epoxy-modified tung oil resin. The AF effectiveness of coating was evaluated toward Staphylococcus aureus (S. aureus, ATCC6538), Escherichia coli (E. coli, ATCC8739) and diatom (Cyclotella sp., FACHB-1635). The nanoTiO2/polymer AF coating showed good antimicrobial activity both under the light and dark conditions by comparison with the pristine TiO2 nanoparticles and bulk polymer. Under light irradiation for 50 min, the AF coating showed only 8.4% and 8% survival rate for S. aureus and E. coli. In addition, The AF coatings exhibited favorable inhibition efficacy toward the growth and adhesion of Cyclotella sp., and the efficacy was enhanced with the increase of TiO2 content. It can be concluded that TiO2 nanoparticles endow the AF coatings with promoted fouling resistance properties.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-23T07:32:12Z
      DOI: 10.1177/09673911211011123
       
  • Accelerated aging behavior and life prediction of low-temperature
           vulcanizable CR–BIIR blend based encapsulant material for undersea
           sensors

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      Authors: PN Mohanadas, T Santhanakrishnan, NR Manoj, T Mukundan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Blends of chloroprene rubber (CR) and bromobutyl rubber (BIIR) with low-temperature vulcanization (LTV) technology were found suitable for the encapsulation of temperature-sensitive undersea sensors. Polymeric blends are susceptible to the aging process due to external environments such as heat, oxygen, ozone, light, and mechanical stresses, etc. Hence, the longevity of these blends for hostile seawater applications is a great concern. The marine aging of rubber blends was not investigated much. In this study, the LTV blends with a curing system based on lead and zinc oxides were subjected to accelerated aging in a 3.5% aqueous solution of NaCl from 40°C to 70°C. The retention of tensile strength, % elongation and modulus properties were estimated. It was observed that aging could lead to an initial increase in the modulus and a considerable decrease in ultimate tensile strength and elongation values with an increase in the aging period. Reduction in elongation at break showed a gradual decrease with an increase in both temperature and exposure time. It was observed that the blends with lead oxide cure system were prone to more degradation than ZnO-based blend. A life of 6.5 years and 5.3 years at 25°C for blends based on ZnO and lead oxide cure systems was estimated. The water diffusion coefficient was found to be of the order of 10−12 mm2 s−1 for both blends.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-21T06:34:30Z
      DOI: 10.1177/09673911211007014
       
  • Behaviour of PLA/POSS nanocomposites: Effects of filler content,
           functional group and copolymer compatibilization

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      Authors: Yelda Meyva Zeybek, Cevdet Kaynak
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The main purpose of this study was to investigate influences of three parameters on the mechanical and thermal properties of the polylactide (PLA) matrix nanocomposites filled with polyhedral oligomeric silsesquioxane (POSS) particles. For the first parameter of “Filler Content”, nanocomposites with 1, 3, 5, 7 wt% basic POSS structure were compared. For the second parameter of “Functional Group,” basic POSS structure having only nonpolar isobutyl groups were compared with three other functionalized POSS structures; i.e. aminopropylisobutyl-POSS (ap-POSS), propanediolisobutyl-POSS (pd-POSS) and octasilane-POSS (os-POSS). Finally, for the third parameter of “Copolymer Compatibilization,” all specimens were compared before and after their maleic anhydride (MA) grafted copolymer compatibilization. Specimens were produced with twin-screw extruder melt mixing and shaped under compression molding. Various tests and analyses indicated that the optimum filler content for the improved mechanical properties was 1 wt%; while the optimum structure for strength and modulus was pd-POSS structure, in terms of fracture toughness it was basic POSS structure. Additional use of MA compatibilization was especially effective for the basic POSS and os-POSS particles.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-12T07:39:08Z
      DOI: 10.1177/09673911211008020
       
  • Development of bamboo polymer composites with improved impact resistance

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      Authors: RM Abhilash, GS Venkatesh, Shakti Singh Chauhan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Reinforcing thermoplastic polymers with natural fibres tends to improve tensile and flexural strength but adversely affect elongation and impact strength. This limits the application of such composites where toughness is a major criterion. In the present work, bamboo fibre reinforced polypropylene (PP) composites were prepared with bamboo fibre content varying from 30% to 50% with improved impact resistance. Homopolymer and copolymer PP were used as the matrix polymer and an elastomer was used (10% by wt.) as an additive in the formulation. Copolymer based composites exhibited superior elongation and impact strength as compared to homopolymer based composites. The adverse impact of elastomer on tensile and flexural strength was more pronounced in homopolymer based composites. The study suggested that the properties of the bamboo composites can be tailored to suit different applications by varying reinforcement and elastomer percentage.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-08T07:33:31Z
      DOI: 10.1177/09673911211009369
       
  • Effect of surface sealant on surface roughness and bacterial adhesion of
           bulk-fill composites

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      Authors: Gunce Ozan, Meltem Mert Eren, Cansu Vatansever, Ugur Erdemir
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Surface sealants are reported to ensure surface smoothness and improve the surface quality of composite restorations. These sealants should also reduce the bacterial adhesion on composite surfaces however, there is not much information regarding their performance on bulk-fill composite materials. The aim of this study was to evaluate the effect of surface sealant application on surface roughness and bacterial adhesion of various restorative materials. Disc-shaped samples were prepared from a compomer, a conventional composite and three bulk-fill composites. Specimens of each group were divided into two groups (n = 9): with/without surface sealant (Biscover LV, [BLV]). Surface roughness values were examined by profilometry and two samples of each group were examined for bacterial adhesion on a confocal laser scanning microscope (CLSM). Bacterial counts were calculated by both broth cultivation and microscopic images. Results were analyzed with one-way ANOVA and Bonferroni/Dunn tests. Following the BLV application, there was a decrease in the surface roughness values of all groups however, only Tetric N-Ceram Bulk and Beautifil-Bulk groups showed significantly smoother surfaces (p < 0.001). There were no significant differences among material groups without BLV application. Evaluating bacterial adhesion after BLV application, conventional composite had the lowest values among all followed by the compomer group. Beautifil-Bulk had significantly the highest bacterial adhesion (p < 0.05), followed by Tetric N-Ceram Bulk group. Without BLV application, there was no significant difference among bacterial adhesion values of groups (p> 0.05). CLSM images showed cell viability in groups. Bulk-fill composites showed higher bacterial adhesion than conventional composite and compomer materials. The surface sealant was found to be highly effective in lowering bacterial adhesion, but not so superior in smoothing the surfaces of restorative materials. So, surface sealants could be used on the restorations of patients with high caries risk.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-08T07:29:10Z
      DOI: 10.1177/09673911211005586
       
  • Structure-property-processing relationships in extruded liquid crystal
           polymer film

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      Authors: Anthony Sullivan, Anil Saigal, Michael A Zimmerman
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Liquid crystal polymers (LCPs) derive favorable mechanical, chemical, and electrical behavior from long-range molecular ordering. The microstructure gives rise to anisotropic bulk properties that are problematic for industrial applications, and thus the ability to model the polymer directionality is essential to the design of isotropic material manufacturing processes. This investigation proposes a modeling methodology to simulate the 3D director field in full-scale film extrusion geometries. Wide-angle x-ray scattering (WAXS) is used to validate the predicted orientation for a standard coat-hanger die, and is compared with macroscopic mechanical, thermal, and dielectric testing of LCP film to illustrate the morphological dependence of the polymer properties. The highly anisotropic orientation state resulting from cast film extrusion is both predicted by the model and confirmed experimentally, and this preferred orientation is shown to correlate with observed anisotropy in the bulk properties. Additionally, a practical implementation of the modeling tool is presented to simulate directionality in two alternative die geometries designed to improve bulk isotropy, and it is demonstrated that the model is capable of simulating the resulting order for large, irregular domains typical of industrial processing.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-07T08:03:18Z
      DOI: 10.1177/09673911211007019
       
  • Alfa fibers for Cereplast bio-composites reinforcement: Effects of
           chemical and biological treatments on the mechanical properties

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      Authors: Mouna Werchefani, Catherine Lacoste, Hafedh Belguith, Chedly Bradai
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The present work is a comparative study of the impact of Alfa fiber modifications on the Cereplast composites mechanical behavior. Various treatments have been employed, including mechanical, soda, saltwater-retting, hot-water treatments and enzymatic treatment using xylanase. Chemical and morphological analyses were carried out in order to determine the changes of the biochemical composition and the dimensions of fibers. Cereplast composites reinforced with Alfa fibers were fabricated using a twin-screw extrusion followed by an injection molding technique with a fiber load of 20 wt. %. Resulting materials were assessed by means of tensile, flexural and Charpy impact testing. Scanning Electron Microscopy analysis was carried out to investigate the interfacial properties of the composites. The results have shown a significant enhancement of mechanical strengths and rigidities for the xylanase-treated fiber composites, owing to the increase of cellulose content, the enhancement of defibrillation level and the improvement of matrix-fiber adhesion. The data proved that the technology of enzymes can be used as a powerful and eco-friendly approach to modify fiber surfaces and to increase their potential of reinforcement.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-05T07:04:40Z
      DOI: 10.1177/09673911211006067
       
  • Effect of vacuum manipulation on inter laminar shear strength and flexural
           strength in double bag vacuum infusion moulding

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      Authors: KI Rana, Z Sajid, Jie Tao, LA Khan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim of this work was to gain insight towards the effect of vacuum manipulation on quality of the laminate by employing an additional bag over the first bag. First (inner) bag is used to infuse resin while second (outer) bag is connected with vacuum pump for compaction process only. Carbon fiber was used as reinforcement while epoxy was used as resin. Effects were related with compaction pressure and volatile management during infusion process. In this study a comparison is also presented between samples manufactured with vacuum infusion moulding employing single and double bag. Two schemes of vacuum manipulation inside the cavities (inner bag and outer bag) were introduced in the manufacturing setup of double bag vacuum infusion moulding (DBVI). Effect of varying vacuum applied levels was related to mechanical properties of the laminates. Samples were manufactured by keeping constant vacuum in the inner bag cavity while varying the same in the outer bag cavity and vice versa. Inter Laminar Shear Strength (ILSS) and flexural strength were used for evaluation process as both of them are critical indicators to assess quality of infused laminates. Testing as per ASTM standards along with image analysis were used for investigation of results. The results showed that employment of double bag, improved the properties under consideration as compared to samples manufactured using single bag. It was found that vacuum manipulation in these two bags can improve the mentioned properties. This improvement in properties was related with volatile management and compaction of fiber in dry and saturated conditions. Finally, a specific combination of vacuum inside the two cavities was also suggested in order to obtain improved properties.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-04-05T07:00:53Z
      DOI: 10.1177/09673911211004206
       
  • DC electrical conductivity retention and acetone/acetaldehyde sensing on
           polythiophene/molybdenum disulphide composites

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      Authors: Ahmad Husain, Sharique Ahmad, Shahid Pervez Ansari, Mohammad Omaish Ansari, Mohammad Mujahid Ali khan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, polythiophene (PTh) and a series of polythiophene/molybdenum disulphide (PTh/MoS2) composites were prepared by in-situ chemical oxidative polymerization method using anhydrous ferric chloride (FeCl3) as an oxidant and chloroform (CHCl3) as a solvent. The successful formation of PTh and PTh/MoS2 composites were confirmed by various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance electron microscopy (TEM). DC electrical conductivity and acetone/acetaldehyde sensing studies were carried out by a four-in-line probe device. PTh/MoS2 composites exhibited significantly improved DC electrical conductivity and acetone/acetaldehyde sensing properties as compared to PTh. The electrical properties were investigated in terms of initial conductivity (i.e. conductivity at room temperature) as well as retention of conductivity, i.e. stability under isothermal and cyclic ageing conditions. The maximum initial conductivity, along with the highest conductivity retention, was observed for PTh/MoS2-2 (PTh/MoS2 composite comprising 10% MoS2 with respect to the weight of thiophene monomer). The initial DC electrical conductivity of PTh, PTh/MoS2-1, PTh/MoS2-2 and PTh/MoS2-3 was found to be 5.72 × 10−5 Scm−1, 4.03 × 10−4 Scm−1, 1.09 × 10−3 Scm−1 and 8.96 × 10−4 Scm−1, respectively. The sensing performance at room temperature has been studied in terms of % sensing response, response/recovery time. All the PTh/MoS2 composites based sensors performed much better than PTh. The % sensing response of PTh, PTh/MoS2-1, PTh/MoS2-2 and PTh/MoS2-3 based pellet-shaped sensors towards acetone/acetaldehyde were affirmed as 30.6/22.9, 69.9/47.3, 93.7/70.3, 78.1/65.1, respectively. The purposed sensing mechanism involved the adsorption of acetone/acetaldehyde vapours on the surface of the sensors where electronic interaction between lone pair of electrons on oxygen atoms of the carbonyl group and charge carriers of PTh was responsible for the change in conductivity.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-29T09:40:06Z
      DOI: 10.1177/09673911211002781
       
  • Improving wear resistance of epoxy/SiC composite using a modified
           apparatus

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      Authors: Amal Nassar, Mostafa Salem, Ismail El-Batanony, Eman Nassar
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      A centrifugal mixing method was developed to disperse ceramic particles inside a thermosetting polymer. Horizontal centrifugal equipment was used to fabricate cylindrical rods from epoxy reinforced with silicon carbide particles. Silicon carbide particles (SiC) are used for the outer coating of epoxy to increase wear resistance. In the centrifugal mixing process, there are three important variables: rotational speed, ceramic percentage and, ceramic size which affect ceramic particle distribution. This paper aims to find the relationship between these variables and the distribution of ceramic particles then determine the optimum conditions to get maximum wear resistance and hardness. From the experiment and analysis, it can be concluded that when mixing speed was greater than 600 rpm, the possibility of air bubbles formation was increased especially for ultrafine particles. Otherwise, the maximum wear resistance and hardness values were found in ultrafine size SiC samples reinforced with 30 wt% which were mixed at a low speed of 300 rpm.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-26T12:43:16Z
      DOI: 10.1177/09673911211002731
       
  • Incorporation and optimization of RGO and GO in SSBR/NR composites expands
           their applicability

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      Authors: Guangyi Lin, Hong Wang, Boquan Yu, Shouyi Liu, Zhenning Liang, Fumin Liu, Runhang Zeng, Shaowei Chen, Tairong Kuang, Kaiben Yu, Baihong Chi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Natural rubber (NR) has poor mechanical properties, which limits its practical application. Filler blending is a simple method that improves the inherent properties of natural rubber and expand its applicability. Using the mechanical mixing process, the effects of graphene oxide (GO) and redox graphene (rGO) on the physical properties, electrical conductivity, thermal conductivity, and air permeability of styrene-butadiene rubber (SSBR)/NR composites were studied. The results show that rGO exhibits efficient filler properties in various aspects, for example, the optimal filling amount of rGO and GO was 1.5 phr. In addition, rGO filled SSBR/NR composites showed satisfactory filler dispersibility. Notably, the better dispersibility of rGO was because of fewer hydrophilic functional groups on the surface which were difficult to agglomerate. The increase of rGO and GO content increased the maximum torque (MH) and minimum torque (ML) of the composite material, and decreases tc90 and tc10. The Payne effect of GO/SSBR/NR composites is more obvious than that of rGO/SSBR/NR composites. In addition, we found that the content of rGO (GO) reached saturation at 2phr. Notably, rGO and GO improved the properties of rGO filled SSBR/NR composites such as the tensile strength of rGO/SSBR/NR composites to 23.9 MPa. This shows the potential application of SSBR/NR composites in wearable electronic devices.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-26T12:15:02Z
      DOI: 10.1177/09673911211001711
       
  • Effect of maleic anhydride grafted polylactic acid concentration on
           mechanical and thermal properties of thermoplasticized starch filled
           polylactic acid blends

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      Authors: Shakti Chauhan, N Raghu, Anand Raj
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polylactic acid (PLA) is blended with native starch or thermo plasticized starch (TPS) for preparing biodegradable composites. However, poor compatibility of PLA with starch results in the composites with inferior mechanical properties. This study examines the effect of Maleic Anhydride-Grafted-PLA (GMAPLA) coupling agent and its concentration on the extent of improvements in mechanical and thermal properties of PLA –TPS blends. Maleic anhydride was grafted on PLA in Haake torque rheometer, characterized and used as the coupling agent. PLA/TPS (wt/wt) blends (70/30 and 50/50) were prepared by twin screw extrusion. GMAPLA at three different levels 5%, 10% and 15% (wt%) with respect to PLA content was taken to study its effect on mechanical properties of blends. Presence of GMAPLA significantly improved the mechanical properties (tensile, flexural and impact strength) of TPS/PLA blends. Among the three concentrations, 10% GMAPLA in the blend was found to give the maximum improvement in strength properties. Dynamic mechanical analysis and thermo-gravimetric analysis indicated no significant effect of GMAPLA content on transition temperatures and thermal degradation behavior of the blends.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-26T12:10:15Z
      DOI: 10.1177/09673911211004194
       
  • Transdermal patch, co-loaded with Pregabalin and Ketoprofen for improved
           bioavailability; in vitro studies

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      Authors: Nida Shafique, Tuba Siddiqui, Muhammad Zaman, Zoya Iqbal, Shahid Rasool, Ambreen Ishaque, Waqar Siddique, Muhammad Nadeem Alvi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The current study was aimed to fabricate a transdermal drug delivery system (TDDS) containing Ketoprofen (KTF) and Pregabalin (PGB) for controlled drug release, avoidance of the first-pass metabolism, and increased patient compliance. TDDS of KTF and PGB were formulated using the solvent casting method. Various ratios of hydrophilic polymer (HPMC) and hydrophobic polymers (Eudragit L-100 and Ethyl Cellulose) were employed for the formulation of transdermal patches. PG and oleic acid were used as a permeation enhancer, and PEG-400 was employed as a plasticizer. Surface morphology has confirmed the uniform distribution of drugs throughout the matrix and the excellent compatibility of the selected ingredients. All the formulation showed folding endurance of more than 300, which exhibited that all patches have suitable mechanical strength. One hundred percent flatness also showed good stability of the patches and suitability of the selected ingredients. In vitro drug permeation studies showed more than 97% and 95% release of PGB and KTF, respectively, during the in vitro dissolution studies. The drug release mechanism investigated with various kinetic models exhibited that the rate of drug release was not dependent on initial concentrations of the drug present in the patches and was following the drug diffusion mechanism.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:52:07Z
      DOI: 10.1177/09673911211004516
       
  • Study on thermal and mechanical behaviors of polypropylene grade
           552R/Cloisite 15A nanocomposites suitable for yarn applications

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      Authors: Ali Farahani, Arsalan Parvareh, Mostafa Keshavarz Moraveji, Davood Soudbar
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The investigation of polypropylene (PP)/clay nanocomposites has received considerable scientific and technological attention during the last decades due to their good mechanical and barrier properties. In the present article, the effects of adding Cloisite15A (C15A) nanoclay in polypropylene (PP) were investigated. PP nanocomposites were prepared by a direct melt mixing method. For better dispersion of C15A, 30 wt% of nanoclay masterbatch was first prepared by melt mixing of PP matrix and acrylic acid grafted PP oligomer (PP-g-AA) in a compounder, before being used to produce nanocomposites with 2 and 5 wt% of C15A. The aim of this work was to used nanoclay filled nanocomposites with suitable properties for cable application like good flame-retardant property; improve dye-ability and resilience of polypropylene. The XRD results indicated an intercalated layer structure for nanocomposites, The SEM examination showed satisfactory dispersion of nanoclay in 2 wt% of C15A and some degree of agglomeration in 5 wt% of C15A. DSC analysis indicated that C15A acts as a nucleating agent and increases crystallinity in the nanocomposite. TGA showed with increasing nanoclay, heat resistance was improved and degradation temperatures increased. Limiting oxygen index (LOI) tests showed increased flame retardancy from 25% for neat polypropylene t0 32.2% for nanocomposites of 5 wt% of C15A. The tensile modulus was improved from 423 MPa for neat polypropylene to 474 MPa for nanocomposites with 5 wt% of C15A. This result indicates that increasing C15A content had a suitable effect on the tensile properties. Melt spinning investigation on low oriented yarn (LOY), draw textured yarn (DTY), and fully drawn yarn (FDY) of 2 wt% C15A nanocomposite showed a reduction of linear density for FDY and an increase of the shrinkage. Furthermore, the obtained results for the improvement of dye-ability and compression resilience showed that PP/C15A is appropriate for textile products.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:51:25Z
      DOI: 10.1177/09673911211003404
       
  • Vibration-based delamination evaluation in GFRP composite beams using ANN

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      Authors: TG Sreekanth, M Senthilkumar, S Manikanta Reddy
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Delamination is definitely an important topic in the area of composite structures as it progressively worsens the mechanical performance of fiber-reinforced polymer composite structures in its service period. The detection and severity analysis of delaminations in engineering areas like the aviation industry is vital for safety and economic considerations. The existence of delaminations varies the vibration characteristics such as natural frequencies, mode shapes, etc. of composites and hence this indication can be effectively used for locating and quantifying the delaminations. The changes in vibration characteristics are considered as inputs for the inverse problem to determine the location and size of delaminations. In this paper Artificial Neural Network (ANN) is used for delamination evaluationof glass fiber-reinforced composite beams using natural frequency as typical vibration parameter. The Finite Element Analysis is used for generating the required dataset for ANN. The frequency-based delamination prediction technique is validated by finite element models and experimental modal analysis. The results indicate that the ANN-based back propagation algorithm can predict the location and size of delaminations in composites with good accuracy for numerical natural frequency data but the accuracy is comparitivelyless for experimental natural frequency data.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:50:24Z
      DOI: 10.1177/09673911211003399
       
  • Evaluating the response of a modified Gent-Thomas strain energy function
           having limiting chain extensibility condition in torsion and azimuthal
           shear

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      Authors: Amir Ghafouri Sayyad, Ali Imam, Shahram Etemadi Haghighi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The purpose of this paper is to investigate the torsion and azimuthal shear of an incompressible hyperelastic cylinder having a modified Gent-Thomas strain energy with limiting chain extensibility condition. First, the torsional response of the modified Gent-Thomas model is obtained analytically and compared with those of Gent-Gent, Gent-Thomas, and Carroll strain energy models where the former model incorporates the limiting chain extensibility condition while the latter two are phenomenological models. The results show the modified Gent-Thomas model to be in better agreement with the experimental data of Rivlin and Saunders on torsion than the other three models. To further evaluate the response of the modified Gent-Thomas model, azimuthal shear deformation of an incompressible hyperelastic cylinder with the modified Gent-Thomas, Gent-Thomas, Gent-Gent, and Carroll strain energies is considered, where the angular displacement in azimuthal shear is determined analytically for the first three models and numerically for the fourth model. It is shown that the strain hardening effect, predicted either by the limiting chain extensibility condition for the modified Gent-Thomas and Gent-Gent models or phenomenologically by the Carroll model, is quite significant in the azimuthal shear response of the incompressible cylinder.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:49:44Z
      DOI: 10.1177/09673911211003394
       
  • Investigation on fracture toughness of polytetrafluoroethylene with impact
           essential work of fracture method

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      Authors: Mustafa Armağan, A Armağan Arıcı
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polytetrafluoroethylene (PTFE) polymer has a wide range of applications in various industries. Therefore, for designers it is essential to know the strength properties of the material under dynamic loads. In this study, pure-PTFE, bronze and carbon filled-PTFE are tested under dynamic load. In addition, pure and carbon filled specimens were used to determine the temperature effect of PTFE. All tests were carried out in the Charpy impact device according to impact essential work of fracture method. At 23°C, pure-PTFE showed the highest impact strengths, bronze filled-PTFE and carbon filled-PTFE showed lower respectively and it has been found that the carbon filler increases the fracture toughness approximately two times at high temperature (150°C). On fracture surfaces phase transitions effects of PTFE and behavior of fillers used were investigated with Scanning Electron Microscope.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:48:43Z
      DOI: 10.1177/09673911211003392
       
  • Thermal post buckling analysis of smart SMA hybrid sandwich composite
           plate

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      Authors: Achchhe Lal, Kanif Markad
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Thermal post-buckling analysis of smart sandwich plates has been presented with the incorporation of shape memory alloy (SMA) and shape memory polymer (SMP) in laminated composite structure under uniform temperature distribution. Buckling analysis is based on higher order shear deformation theory (HSDT) with von Karman nonlinearity by finite element method (FEM). Evaluation of critical buckling temperature has been performed under the action of inplane uniform temperature distribution for different boundary conditions, plate’s aspect and thickness ratio, modulus ratio, ply orientations of smart SMA hybrid sandwich composite plate. Shape memory alloys itself acting uniquely under temperature variation and with SMA reinforced SMP laminated composite plate this phenomenon extended further under dynamic temperature condition for thermal buckling behavior. Also SMA with different strain rate and variation in SMA volume fraction is also presented to understand the cumulative buckling behavior.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-24T09:48:24Z
      DOI: 10.1177/09673911211001276
       
  • Bio-sourced vinyl ester resin reinforced with microfibrillar cellulose:
           Mechanical and thermal properties

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      Authors: Eric Desnoes, Lotfi Toubal, Dominic Thibeault, Amel Hadj Bouazza, Daniel Montplaisir
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      New thermoset composite material made from cardanol-based resin blended with microfibrillar cellulose was compared to petroleum-based vinyl ester and glass-fiber-reinforced unsaturated polyester in terms of mechanical, thermal, rheological and surface properties of produced polymers and composites. The bio-sourced material was less resistant than the commercial vinyl ester but comparable to the unsaturated polyester resin. Microfibrillar cellulose increased the tensile strength and modulus but increased the resin viscosity and decreased the mixture homogeneity. The bio-sourced and commercial resins displayed similar hydrophobic behavior, and cellulose slightly decreased composite hydrophobicity. The glass transition temperature of the bio-sourced material was comparable to that of the unsaturated polyester. Thermal decompositions of composites and thermoset polymers were also similar. Cellulose and cardanol thus may be adequate as sustainable components in the composite materials industry.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-19T09:58:55Z
      DOI: 10.1177/09673911211002046
       
  • Experimental damping ratio evaluation using Hilbert transform in
           filament-wound composite plates

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      Authors: Enzo Costamilan, Alexandre Marks Löw, Marcos Daniel de Freitas Awruch, Sandro C Amico, Herbert Martins Gomes
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim of this work is the evaluation of damping ratio in composite materials with orthogonal fiber orientation based on experimental and numerical techniques. In this study, the logarithmic decrement and the envelope techniques calculated using Hilbert transform are used. Carbon fiber/epoxy composites manufactured by filament winding are dynamically tested in free vibration. Post-processing and data analysis are performed with the developed codes. These comprise the use of a band-pass filter to isolate the first fundamental frequency from the other modes of vibration and noise present in the acquired signal. Then, the Hilbert transform is used to estimate the envelope of the vibration signal and the exponential curve is adjusted to obtain the envelope, in order to evaluate the structural damping ratio. Comparisons with a fitted finite element model are used for validation. The results revealed that damping varied proportionally with the number of layers, the ply orientation and, less evidently, with the length of the samples.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-17T10:41:48Z
      DOI: 10.1177/09673911211002063
       
  • Effect of layer thickness on residual monomer release in polymerization of
           bulk-fill composites

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      Authors: Vahti Kılıç, Feridun Hurmuzlu, Yılmaz Ugur, Suzan Cangul
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim of the present study was to investigate and compare the quantity of residual monomers leached from the bulk-fill composites with different compositions polymerized at varying layer thickness. Three bulk-fill (X-tra-fil, Beautifil Bulk Restorative, Fill-Up) and a nanohybrid composite (Filtek Z550) were used for the study. The composite resin samples were prepared with a stainless steel mold. For each composite, two groups were constructed. The samples in the first group were prepared using the 2 + 2 mm layering technique. In the second group, the composite samples were applied as a 4 mm-thick one layer and polymerized. Then, each composite samples were kept in a 75% ethanol solution and residual monomers released from composite resins were analyzed with an HPLC device after 24hour and 1 month. The data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Except the Fill-Up, all of residual monomer elution from the bulk-fill composites was significantly affected by the layer thickness (p < 0.05). The greatest monomer release was detected at 1 month after polymerization as a single 4 mm layer for Beautifil Bulk Restorative. Fill-Up composite showed similar residual monomer release in polymerization at different layer thicknesses compared to other composite resins. In the 2 + 2 mm layering technique, the least monomer elution was detected in the Filtek Z550 composite group. While Bis-GMA was the most released monomer in X-tra fil composite, UDMA was the most released monomer in all other composite resins. During polymerization of the bulk-fill composite, the layer thickness of the composite applied may affect the amount of residual monomers released from the composite resins. Conventional composites may release less monomer than bulk-fill composites when used with layering.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-16T05:40:54Z
      DOI: 10.1177/0967391121999588
       
  • Electrical conductivity and rheological properties of carbon black based
           conductive polymer composites prior to and after annealing

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      Authors: Qingsen Gao, Jingguang Liu, Xianhu Liu
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-11T10:08:17Z
      DOI: 10.1177/09673911211001277
       
  • Effective removal of Basic Red 12 dye by novel antimicrobial trimellitic
           anhydride isothiocyanate-cross-linked chitosan hydrogels

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      Authors: Nadia A Mohamed, Nouf F Al-Harby, Mawaheb S Almarshed
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Dyes removal from wastewater of industries is considered the prime demand of the environment. Three trimellitic anhydride isothiocyanate-cross-linked chitosan hydrogels, previously reported as novel antimicrobial agents, were investigated for the first time in this work as adsorbents for Basic Red 12 (BR 12) cationic dye. These hydrogels behave as polyanionic materials. Their adsorption capacity for the BR 12 dye increased significantly with increasing both the temperature, the solution pH and their cross-linking content. Their adsorption fitted to the pseudo-second-order kinetic model. Their adsorption isotherms conform to the Langmuir model suggesting that the adsorption nature is a monolayer having an optimum sorption capability of 38.27 mg g−1 and removal efficiency of 97.38%. The results proved that the adsorption process is remarkably proceeded by chemisorption phenomenon. The data of adsorption thermodynamics indicate that the adsorption is an endothermic process. The regeneration and reuse of the hydrogels were possible. Thus, incorporation of the functionality of the cross-linker into chitosan within the same structure efficiently enhanced its features. It is a good manner for achieving appropriate series of efficient adsorbents which are considered as favorable nominees in the field of basic dyes removal.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-10T09:48:56Z
      DOI: 10.1177/0967391121999364
       
  • Mechanical characterization of hydrolysis effects on the stiffness of
           bioabsorbable polymeric filaments: An experimental and modeling approach
           based on a simple constitutive damage model

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      Authors: Thiago André Carniel, Paulo Bastos de Castro, André Luiz Grando Santos, Carlos Rodrigo de Mello Roesler, Everton Rafael Breitenbach, Gean Vitor Salmoria, Mário Augusto Morozo, Pablo Antônio Colaço, Márcio Antônio Fiori, Eduardo Alberto Fancello
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This manuscript presents an experimental and modeling approach in order to characterize the stiffness loss of bioabsorbable polymer filaments due to hydrolysis. In this regard, bioabsorbable suture yarns (poly(lactic-co-glycolic) acid—PLGA) were chosen as a representative material for the present investigation. The observed mechanical response was characterized by means of a thermodynamically consistent constitutive variational framework. Usually, two different damage variables are assumed to take place in this class of materials: a hydrolytic damage (long-term degradation) and a strain-driven damage (short-term degradation). This work concerns the proposition of a constitutive model that only considers the hydrolytic damage, in which a specific strain energy and a proper dissipation damage potential were tailored to model the tested material. A nonlinear curve fitting procedure based on Particle Swarm Optimization was performed to identify the constitutive parameters. A set of numerical simulations demonstrates the effectiveness of the proposed constitutive model to predict damage-induced creep and damage-induced stress relaxation, behaviors that can be used as design criteria in absorbable implants. The main achieved results show that the proposed constitutive approach leads to a simple but effective model capable to drive the first steps in the design of absorbable biomedical devices. The present variational framework can be extended to study the constitutive response of other bioabsorbable polymers, accounting for viscous and/or plastic behaviors.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-08T09:44:01Z
      DOI: 10.1177/0967391121998822
       
  • Mechanical, thermal and ablative behavior of organo nanoclay added carbon
           fiber/cyanate ester resin composites and effect of heat flux on its
           ablative performance

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      Authors: Golla Rama Rao, Ivautri Srikanth, K Laxma Reddy
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Nanoclay added cyanate ester resin (Type I) composites were fabricated by adding different weight percentages (0,1,2,4 & 6 wt%) of organo-modified Montmorillonite (o-MMT) and tested for dispersion by Small angle X-ray scattering(SAXS), thermal stability using Thermogravimetric analyser (TGA) and curing behavior using Differential scanning calorimeter (DSC). This data was correlated with the thermomechanical properties of nanoclay added carbon fiber reinforced cyanate ester resin composites (C-CE composites /Type II). Interlaminar shear strength (ILSS), flexural strength of type II composites increased by about17%, 21% respectively at 2 wt% addition of nanoclay although at this loading nanoclay was found to show intercalation.Thermal stability of type II composites got reduced whereas the ablation rate has increased for type II composites with increased loading of nanoclay. However, percentage increase in ablation rate was found to be lower when type II composites were tested at 5000 kWm−2as compared to the ablation testing carried out at 1250 kWm−2. Scanning electron microscopy studies indicates significant melting of nanoclay at high flux resulting in additional protection mechanisms for the composites at high flux. Present study indicates the possibility of using o-MMT nanoclay for improved mechanical properties of C-CE composites used in thermal protection systems (TPS).
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-04T10:05:44Z
      DOI: 10.1177/0967391121998833
       
  • Tribological response of polycarbonate and acrylonitrile butadiene styrene
           blends containing fixed amounts of Kevlar fibre and molybdenum disulphide
           with varying quantities of betel nut powder

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      Authors: T Pramod, P Sampathkumaran, N Puneeth, RRN Sailaja, S Seetharamu, A Sathyanarayana Swamy, Kishore
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, the composites with incorporation betel nut powder at three levels (10, 18 and 25%) in Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) matrices having Kevlar Fibres (KF) and Molybdenum Disulphide (MoS2) nano particles in fixed amounts are looked into for their tribological characteristics. The effect of hardness, surface roughness and density was evaluated. FTIR and X-ray diffraction (XRD) studies have been carried out to identify the phases. The effects of load on the slide wear loss and coefficient of friction of the composites were determined using Pin on Disc set up. The wear test pertaining to the betel nut bearing (BNP) composites were compared with those of betel nut free ones i.e. PC/ABS/KF/MoS2. The results revealed that with increase in load, the wear loss increases. Further with increase in betel nut powder concentration from 10% to 25% there is a decrease in wear loss as well as coefficient of friction. The surface morphology of the worn surface were examined using Scanning Electron Microscopy (SEM) which revealed higher plastic deformation, debris formation and furrowing in BNP free systems compared to betel nut bearing ones.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-04T10:05:04Z
      DOI: 10.1177/0967391121998823
       
  • Quasi-static and dynamic nanomechanical characterization of PMMA/ZnO
           

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      Authors: B Krishna, A Chaturvedi, Neelam Mishra, K Das
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Polymer nanocomposite films, comprising of polymethylmethacrylate (PMMA) as the matrix and zinc oxide (ZnO) nanoparticles as reinforcement, have been prepared using ultrasonication and spin-coating techniques, with ZnO content up to 20 wt.%. The effect of the processing on the microstructure and nanomechanical properties have been investigated. The nanocomposite film thickness is found to vary from 2.4 ± 0.2 µm for pristine PMMA to 33.1 ± 0.5 µm for PMMA/20 wt.% ZnO nanocomposite. Quasi-static nanoindentation showed that the indentation modulus varied from 4.68 ± 0.07 GPa for pristine PMMA to 5.04 ± 0.14 GPa for PMMA/20 wt.% ZnO nanocomposite, while the indentation hardness varied from 275.94 ± 5.67 MPa to 292.39 ± 10.88 MPa in the same range. However, the highest indentation modulus and the highest hardness are exhibited by PMMA/10 wt.% ZnO nanocomposite. Scanning electron microscopy of the synthesized films provided the evidence behind such variation in material properties. In addition, the experimentally obtained elastic moduli were compared with values predicted by using Eshelby-Mori-Tanaka micromechanics. Nanoindenter-based dynamic mechanical analysis of the PMMA nanocomposite thin films revealed the variation of storage modulus, loss modulus and loss factor of the films in the frequency range of 10 Hz to 201.5 Hz. For all PMMA/ZnO nanocomposites, the storage modulus is found to increase monotonically from 10 Hz to ∼100 Hz, beyond which the values reached a plateau. The loss modulus and loss factor for all PMMA/ZnO nanocomposites are found to decrease with increasing frequency. These results form an essential step toward establishing process-structure-nanomechanical property relationships for PMMA/ZnO nanocomposite films.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-04T10:04:04Z
      DOI: 10.1177/0967391121998484
       
  • Optimal radiation shielding capacity and thermal properties of poly(methyl
           methacrylate) films enhanced with different metal complexes

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      Authors: Heba A Saudi, Hossam M Gomaa, El-Said H El-Mosallamy, Saeid M Elkatlawy
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Samples of pure poly(methyl methacrylate) (PMMA) and PMMA enhanced with metal complexes of Zn, Cd, and Hg were synthesized via catalytic chain transfer polymerization. Structural analysis, by means of XRD, showed the amorphous nature of the studied samples which meant high homogenous dissolution of the metals (Zn, Cd and Hg) into the polymer matrix. Density values increased linearly with respect to atomic radius of the incorporated metals. Addition of such elements causes an increase in mass attenuation coefficients and a remarkable decrease in the Half Value Layer (HVL) values, in comparison to existing standard shielding materials. Thermal studies by DSC indicated highly homogenous internal structure of the studied samples, with slight decrease in the Tg value when introducing metals due to heterogeneous nucleation agent role of the Cd, Zn and Hg. All observations and results suggest the studied materials to be used as promising and proper aprons for medical radiation shielding applications.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-03-03T10:50:40Z
      DOI: 10.1177/0967391121998490
       
  • Preparation and applications of fluoroalkyl end-capped
           vinyltrimethoxysilane oligomeric silica/chemically modified cellulose
           fibers composites

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      Authors: Hideo Sawada, Shunta Yamamoto, Kako Tono, Katsumi Yamashita
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(CH2-CHSi(OMe)3)n-RF: n = 2, 3; RF = CF(CF3)OC3F7: RF-(VM)n-RF] was found to undergo the sol-gel reaction under alkaline conditions in the presence of chemically modified cellulose fibers treated with N-methylglucamine units (MeGlu) [Cellu-fiber-MeGlu] and treated with iminodiacetic acid units (ImDia) (Cellu-fiber-ImDia) to provide the corresponding fluorinated oligomeric silica/Cellu-fiber-MeGlu composites [RF-(VM-SiO3/2)n-RF/Cellu-fiber-MeGlu] and /Cellu-fiber-ImDia composites [RF-(VM-SiO3/2)n-RF/Cellu-fiber-ImDia], respectively. Dodecane and water contact angle measurements showed that these obtained composites can supply a superamphiphobic characteristic on their composite powders surface. The RF-(VM-SiO3/2)n-RF/Cellu-fiber-ImDia composites were applied to the packing material for the column chromatography to separate the mixture of hydrocarbon and fluorocarbon oils. In addition, the RF-(VM-SiO3/2)n-RF/Cellu-fiber-ImDia composites were found to have more effective removal ability for fluorinated aromatic compounds than that for the corresponding non-fluorinated ones from aqueous methanol solutions. Interestingly, it was demonstrated that the RF-(VM-SiO3/2)n-RF/Cellu-fiber-MeGlu composite powders are also applicable to the fabrication of liquid marbles, which are millimeter-sized liquids such as water, glycerine, ethylene glycol and dodecane stabilized by the adsorbed composite powders at air-liquid interfaces.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-16T09:52:41Z
      DOI: 10.1177/0967391121992923
       
  • Green synthesis of chitosan/nanosilver hybrid bionanocomposites with
           promising antimicrobial, antioxidant and anticervical cancer activity

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      Authors: Annu, Shakeel Ahmed, Ranjeet Kumar Nirala, Ravi Kumar, Saiqa Ikram
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Being a versatile biopolymer, chitosan has been used to synthesize silver nanoparticles (SNPs) impregnated hybrid chitosan-nanosilver bionanocomposite (CSSNC) films via a green ex-situ and in-situ route using fruit waste extract. CSSNC hybrid bionanocomposite films were prepared in six different concentrations and characterized by using different techniques i.e. UV-visible spectroscopy, FT-IR spectroscopy, Thermogravimetric analysis, X-Ray Diffraction and Scanning Electron Microscopy. Among the CSSNC, CS9AGE1 has been optimized for further biological assays for which the antimicrobial activity revealed the highest zone of inhibition against E. coli (20 mm) and S. aureus (17.5 mm). The antioxidant activity revealed dose-dependent radical scavenging against 2,2-diphenyl-1-picrylhydrazyl (DPPH) (50 µg mL−1), nitric oxide (50 µg mL−1) radical, and total reduction capability (40 µg mL−1). Furthermore, low percent cell viability was observed for cancerous cells at a concentration of 50 µg mL−1 against cervical cancer cells, (HeLa cell line). Therefore, the overall accomplishment confesses a strong potential of CSSNC fabrication via an eco-friendly route exhibiting remarkable anticancer and antioxidant activity and hence provide a gateway to be further explored in the biomedical sciences.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-11T10:06:57Z
      DOI: 10.1177/0967391121993977
       
  • The rheological behaviour and thermal ageing characteristics of
           PP/MWCNT/glass fibre multiscale composites

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      Authors: N Rasana, K Jayanarayanan, Krishna Prasad Rajan, Aravinthan Gopanna
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Multiscale hybrid composites were prepared using varying weight percentages (0 to 5) of multiwalled carbon nanotubes (MWCNTs) as nanofiller and a fixed weight percentage (20) of short glass fibres as micro filler (in polypropylene (PP) matrix. The shear and extensional viscosity of the composites was measured using a capillary rheometer. It was observed that even at higher shear rates the synergism of micro and nanofillers in the matrix significantly enhanced the melt viscosity. The complex nanotube network entanglement with micro fillers and PP chains imparted restrictions to the polymer chain movements. The prepared samples were subjected to thermal ageing at 100°C for 4 days in hot air oven. After ageing, multiscale composite with 3 wt% MWCNTs exhibited 28.57% enhancement in strain at break, whereas the tensile strength and modulus reduced by 6.8% and 8% respectively. The fracture toughness properties like strain energy release rate and critical stress intensity factor were not affected for multiscale composite at the optimum content of 3 wt% MWCNT, even after thermal ageing.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-10T09:30:31Z
      DOI: 10.1177/0967391121992909
       
  • The effect of fiber orientation on mechanical properties and machinability
           of GFRP composites by end milling using cutting force analysis

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      Authors: Abburi Lakshman Kumar, M Prakash
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In recent years, glass fiber-reinforced polymer (GFRP) composite materials have become a viable alternative material for different engineering applications due to their superior/excellent properties. The strength of the composite is positively related to the orientation of the fiber material. However, the machinability is still a problem when components are manufactured using the GFRP composites due to their anisotropic properties. The aim of this analytical research paper is to investigate the influence of fiber orientation on the strength and machinability in slot milling of GFRP fabricated using the vacuum infusion method. The fiber orientations of 0°/90° and ±45° are used for the fabrication of GFRP composite laminates. The experiments were conducted using an orthogonal array. Analysis of variance was employed to determine the influence of milling parameters such as cutting speed, transverse feed rate, and axial depth of cut (A.D.O.C.) for the surface finish (Ra), cutting force, and Machinability index (MI). The MI is calculated based on specific cutting pressure. The influence of fiber orientation on the cutting force and surface topography was analyzed. It was concluded that the cutting forces were significantly influenced by the fiber orientation and not affected by the machining parameters. The results revealed that the transverse feed rate was the primary influencing parameter responsible for the increase in MI (40 to 56%). The A.D.O.C. was accountable for the increase in cutting force (55 to 94%). Similarly, the cutting speed influenced Ra, which increased from 17 to 37%.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-08T09:34:04Z
      DOI: 10.1177/0967391121991289
       
  • Effect of hydrothermal ageing on the mechanical behaviour of graphene
           nanoplatelets reinforced basalt fibre epoxy composite pipes

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      Authors: Harun Sepetcioglu, Alper Gunoz, Memduh Kara
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This research studies the effect of the addition of graphene nanoplatelets (GnPs) on the mechanical behaviour of composite pipe materials exposed to hydrothermal ageing, aiming to increase their service life. For this reason, 0.25 wt.% GnPs reinforced and unreinforced filament wound basalt fibre reinforced epoxy composite pipes (BFRPs) were produced. BFRPs were exposed to a hydrothermal ageing process in order to examine the effects of water absorption behaviour on mechanical properties. Hydrothermal ageing processes were carried out by immersing the samples in distilled water at 80°C for different periods such as 15, 30, 45 and 60 days. Following the ASTM standards, the tensile, density and hardness properties of water-exposed GnPs reinforced and unreinforced BFRPs were examined and compared with unexposed specimens. As a result, while water absorption caused a remarkable loss in the mechanical properties of BFRPs, the adverse effects of water absorption on mechanical properties were minimized by the presence of GnPs.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-05T09:56:20Z
      DOI: 10.1177/0967391121992939
       
  • Properties of styrene-ethylene-butylene styrene block copolymer/exfoliated
           graphite nanoplatelets nanocomposites

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      Authors: Marissa A Paglicawan, Josefina R Celorico
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Three different types of styrene-ethylene-butylene-styrene block copolymer (SEBS) with varying ratios of styrene and rubber were melt-compounded with exfoliated graphite nanoplatelets at different loadings. The morphological, thermal, and mechanical properties of the nanocomposites were studied and compared. Morphological observation under SEM and AFM found that the xGnPs were dispersed at the sub-micron level throughout the SEBS matrix. Good interfacial adhesion between the xGnPs and the matrix was also observed. However, the behavior of dispersion was dependent on the styrene/rubber content. SEBS with higher styrene content showed better dispersion and strong interfacial adhesion between the xGnPs and SEBS matrix. These results contributed to the enhancement of the tensile strength of the nanocomposites. Low styrene content behaved like rubber that resulted in low tensile strength but higher elongation compared to SEBS of different amounts of styrene. The XRD patterns indicated that the melt compounding process did not change the d-spacing of xGnPs in all types of SEBS. From the thermal analysis, there was no change in the glass transition of the polymer and no improvement in the thermal stability of the nanocomposites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-05T09:55:22Z
      DOI: 10.1177/0967391121991290
       
  • Development and characterization of sodium alginate/poly(sodium
           4-styrenesulfonate) composite films for release behavior of ciprofloxacin
           hydrogen chloride monohydrate

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      Authors: M Sohail Sarwar, Abdul Ghaffar, Qingrong Huang
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Biopolymers, in particular polysaccharides, have attracted considerable interest in the field of drug delivery due to their biodegradable and biocompatible nature. This study is focused on the preparation and characterization of drug delivery devices based on sodium alginate (SA) composite films with poly(sodium 4-styrenesulfonate) (PSS). The prepared composite films were characterized for the determination of physiochemical properties, molecular interactions, and drug release behavior. The possible intermolecular hydrogen bonding between SA and PSS was determined by ATR-FTIR spectroscopy. Surface characterization was done using AFM. Polymeric films consisted of pristine SA and PSS exhibited relatively uniform and flat surfaces. However, the composite films showed phase separation that became more prominent as the concentration of PSS in the composite films was increased up to 40% (w/w). The contact angle (CA) values, using deionized water as a function of time (s), were ranging from 74° to 90°, and a decrease in CA (64° to 76°) was recorded for each composite film till 40 s. These CA values revealed that all the composite films were hydrophobic. It was observed that as the concentration of PSS in the films increased, hydrophobicity slightly varied as compared to the blank films of SA and PSS. Maximum CA (89°) was shown by a composite film having SA/PSS (90/10). Ciprofloxacin hydrochloride monohydrate (CPX), a model drug, loaded in a suitable composite film (cross-linked with 0.3 M CaCl2 solution) and drug release was evaluated in pH 1.2 simulated gastric fluid (SGF) and pH 7.4 phosphate buffer saline (PBS) solution. In SGF, around 90% of the model drug was released in 110 min that was approximately 77% in the case of PBS. Therefore, it was concluded that a sustained drug release behavior was exhibited in SGF as compared to PBS solution. These results suggest that these films are a promising and may potentially be subjected to study further their drug delivery behavior in applications like wound dressing.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-02-03T09:57:16Z
      DOI: 10.1177/0967391121990278
       
  • Photostable electroactive polymer based nanocomposite films for the
           protection of mild steel from corrosion

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      Authors: I Pugazhenthi, S Mohammed Safiullah, K Anver Basha
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The deterioration of organic film due to chemical and UV attack is an increasing concern in paint technology. Thus, the development of new material for UV blocking anticorrosive film draws significant attention in materials science research. This can be achieved by the incorporation of wide band gap nanoparticles like titania (TiO2NPs) and zirconia (ZrO2NPs) in electroactive polymer namely poly(pyridine-4-yl-methyl) methacrylate-co-butyl methacrylate (poly(PyMMA-co-BMA)) film (hybrid film) for the protection of mild steel (MS) from corrosion. The TiO2NPs and ZrO2NPs in combination with polymer absorb more UV light which prevents the deterioration of film. The hybrid material made of poly(PyMMA-co-BMA) and wide band gap nanoparticles was prepared by in situ solution polymerization. The resultant hybrid materials were characterized by various techniques namely X-ray diffraction studies (XRD) and transmission electron microscopy (TEM). The hybrid materials were deposited as film on the MS by spin coating method. The anticorrosive performance of hybrid films was analysed out using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The surface examination of films were characterized with scanning electron microscope to confirm the formation of poly(PyMMA-co-BMA) and its different nanocomposite films on MS. The UV blocking studies were also carried out using UV-visible spectroscopy. The electrochemical and optical studies reveals that the poly(PyMMA-co-BMA)/TiO2 film on MS in 3.5% (w/v) NaCl provides better protection against corrosion than ZrO2 based nanocomposite hybrid film.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-19T10:08:58Z
      DOI: 10.1177/0967391120986506
       
  • Mechanical and thermomechanical properties of vinyl ester/polyurethane IPN
           based nano-composites

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      Authors: Jagesh Kumar Ranjan, Sudipta Goswami
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Interpenetrating polymer networks of vinyl ester (VE) resin and polyurethane (PU) were synthesized using blend ratio of 93:7(w/w). Two sets of nanocomposites based on i) pure vinyl ester and ii)VE/PU IPN(93VE), were prepared with organically modified silica nanoparticle (OMS) as filler by 1, 2, 3 and 5% weight of the matrix resin. All the nanocomposites were characterized in terms of mechanical and thermomechanical properties.VE/silica nanocomposite with 2% filler (VES2) showed improvement in ultimate tensile strength by 83.5% and toughness by 42% compared to that of VE resin itself. The IPN based nanocomposite, 93VES2, exhibited 31.14%, 10.8% and 18%greater tensile strength, Young’s modulus and toughness respectively in comparison to that of the base 93VE IPN. IPN based nanocomposites were tougher than VE based nanocomposites. Storage modulus of nanocomposites was lower than that of 93VE and VE matrix system. Higher tanδmax of the 93VE/OMS nanocomposites than that of the 93VE matrix was indication of more elastic nature of the later. Smaller size of dispersed domains was found in SEM micrographs for IPN based nanocomposites than that in micrographs of VE based nanocomposites of corresponding composition.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-18T09:56:08Z
      DOI: 10.1177/0967391120987349
       
  • High density polyethylene/wood flour composite: Optimization of processing
           temperature, processing time and coupling agent concentration

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      Authors: Zahra Ranjbarha, Parviz Aberoomand-Azar, Javad Mokhtari-Aliabad, Seyed Amin Mirmohammadi, Mohammad Saber-Tehrani
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Wood plastic composites (WPCs) consisting of high density polyethylene (HDPE) reinforced with high-loading (55 wt%) of wood flour (WF) were fabricated with melt-blending technique. In this compounding method, processing parameters such as different mixing temperatures (of 165, 180 and 195°C), mixing times (of 5, 10 and 15 minutes) and coupling agent contents (of 2 and 4 wt%) were evaluated. Prepared specimens were analyzed with tensile, Izod, shore D, DMTA, short-term creep, DSC, TGA, water absorption and water contact angle characterizations. Results revealed that mixing temperature of 180°C, mixing time of 10 minutes and coupling agent concentration of 4 wt% were found as the best processing conditions. The mentioned conditions provided enhanced dispersion of WF particles within the HDPE matrix, due to optimum viscosity of the polymer melt and effective residence time of compound in the mixer, and beside them efficient interfacial adhesion between WF and polymer matrix.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-13T10:00:55Z
      DOI: 10.1177/0967391120987338
       
  • Moldability improvement in microinjection molding via film lamination

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      Authors: Dah Hee Kim, Young Seok Song
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The purpose of this study is to integrate a polymeric film onto a mold to impede thermal heat transfer during resin infusion. A thin plastic plate was fabricated by using microinjection molding. A polyimide (PI) film was laminated onto a mold in an effort to produce a thin light guide plate (LGP). The film could decelerate the solidification of molten polymer in the cavity of mold and enhance the wall slip of resin on the mold. The insulation effect was modeled numerically. The surface roughness and pattern transfer characteristics of the LGP were evaluated. It was found that the fluidity of the resin increased due to the decreased skin layer during mold filling. The results showed that the strategy proposed in this study could help decrease the thickness of LGP effectively when manufacturing the part via injection molding.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-13T10:00:54Z
      DOI: 10.1177/0967391120986503
       
  • Studies on thermal and degradation kinetics of cellulose
           micro/nanoparticle filled polylactic acid (PLA) based nanocomposites

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      Authors: Achal Bhiogade, Murugasamy Kannan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      The aim of this work is to understand the effect of concentration of plasticizer, particle size and wt% of nanoparticles on nanocomposites by fabricating poly lactic acid (PLA) based bio-nanocomposites. The bio-nanocomposites were prepared by a solution casting method with PLA as the matrix, chloroform as solvent and poly ethylene glycol (PEG) as plasticizer. Microcrystalline cellulose (MCC) and cellulose nanocrystal (CNC) were used as reinforcements in 1, 3 and 5 wt% to modify the properties of the bio-nanocomposite. The degradation kinetics of the PLA based composites were determined by using the Coats-Redfern equation over the range of 0-5 wt% of MCC and CNC. Fabricated PLA based composite films were analyzed by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM). The analyses showed that the amount of PEG, MCC and CNC affected the degree of crystallinity. DSC results showed that the MCC/CNC content level affected the degree of crystallinity compared to neat PLA. The FTIR showed a free hydroxyl group (−OH) present in the system. The TGA analysis showed that the PLA/MCC3%/ PEG 10% composition had the highest stability compared to the other compositions but less than neat PLA.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-13T10:00:54Z
      DOI: 10.1177/0967391120987170
       
  • Mechanical properties of multiwall carbon nanotubes/unidirectional carbon
           fiber-reinforced epoxy hybrid nanocomposites in transverse and
           longitudinal fiber directions

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      Authors: Saeedeh Saadatyar, Mohammad Hosain Beheshty, Razi Sahraeian
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-13T10:00:53Z
      DOI: 10.1177/0967391120986516
       
  • Improvement in cavitation resistance of poly (vinyl butyral) composite
           films with silica nanoparticles: A technical note

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      Authors: Vera Obradović, Marija Vuksanović, Nataša Tomić, Dušica Stojanović, Tatjana Volkov Husović, Petar Uskoković
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study poly (vinyl butyral)/silica (PVB/SiO2) composite films were subjected to the cavitation process. The experiments were carried out with a 10 wt.% PVB solution in ethanol. Silica nanoparticles were added into the solution in different concentration of 1, 3 and 5 wt.% SiO2 in regard to PVB. Composite films were cast from these solutions and subjected to ultrasonic cavitation. Optical images of their surfaces were analyzed before and after cavitation, by Image-Pro Plus software. The results revealed that the PVB film with 5 wt.% SiO2 nanoparticles demonstrated the greatest improvement in microhardness with the best cavitation resistance compared to other films.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-08T10:37:28Z
      DOI: 10.1177/0967391120986505
       
  • Synthesis of a multicomponent silica aerogel-containing nanocomposite for
           efficient sound absorption properties

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      Authors: Mansoureh Hamidi, Parvin Nassiri, Homayoon Ahmad Panahi, Lobat Taghavi, Saeed Bazgir
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In this study, the sound properties of four types of nanocomposites have been investigated. To this end, the prepared samples were measured by the impedance tube model BSWA-SW 422, SW477. It was found that the Sound Absorption Coefficient (SAC) of all samples was increased at high frequencies relatively well. The highest SAC at medium and low frequencies was related to the nanocomposite D. The results of sound Transmission Loss (TL) of nanocomposites showed that the TL value for the nanocomposite D (optimum sample) was higher at all frequencies compared to other nanocomposites. The results confirmed that adding organic and mineral materials to the silica aerogel (SA) simultaneously improves its sound properties. By measuring the Sound Pressure Level (SPL) around the enclosure without optimum sample and with optimum sample in the four sound ranges, we found that using nanocomposite D can significantly reduce the noise. According to this study, SA/polyester nonwoven layer/pan nanofibers/nanoclay nanocomposite (nanocomposites D) have great sound absorption properties, which can be used in different environments.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-06T04:03:33Z
      DOI: 10.1177/0967391120985741
       
  • The self-healing investigations on fiber-reinforced polymer composites
           through a novel compartmented microcapillary approach

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      Authors: Deepak Jain, Aviral Gupta, Sumit Mahajan
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      This paper presents the experimental self-healing investigations on fiber-reinforced polymer (FRP) composites using a novel in-situ healing approach. During the preparation of polymer composites, the monomer Dicyclopentadiene (DCPD) was embedded as the healing agent. The compartment hollow glass microcapillaries were used to serve the localized distribution of the healing agent. To determine the viability of the proposed microcapillary approach, several flexural tests were conducted to initiate the damage and subsequent realization of self-repair activity. The healing was initiated through the polymerization of DCPD in the presence of Grubb’s catalyst (first and second generation). Once healed, the specimens were tested cyclically to evaluate the recovery of flexural strength. A post-failure healing efficiency as high as 72% has been observed. SEM and XRD investigations have been conducted for the microstructural investigations. These investigations support the potential applications of the proposed concept of embedding the bulk with the microcapillaries.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-06T04:01:09Z
      DOI: 10.1177/0967391120985740
       
  • Poly(methyl methacrylate)/SiO2 nanocomposites: Effects of the molecular
           interaction strength on thermal properties

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      Authors: Djilali Boulerba, Abdelhalim Zoukel
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      Poly(methyl methacrylate)/silica nanocomposites membranes were prepared by simple solution mixing method using three different solvents (acetone, acetonitrile and chloroform). The structure and thermal properties of these nanocomposites were investigated by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and environmental scanning electron microscope (ESEM). The infrared spectra confirm that the strongest H-bond interaction between the PMMA and silica was found when using chloroform solvent. In the case of thermal properties, the DSC and TGA analyses show significant improvement in thermal stability and glass transition temperature (Tg). Furthermore, the ESEM micrographs prove the structure stability of these synthesized nanocomposites. The results demonstrate that the solvent that lead to form the strongest H-bond interaction between the PMMA carbonyl groups and silica silanol groups (as chloroform solvent) will be more efficient in the synthesis of PMMA/SiO2 nanocomposites.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-06T04:00:29Z
      DOI: 10.1177/0967391120985710
       
  • Cumulative acoustic emission energy for damage detection in composites
           reinforced by carbon fibers within low-cycle fatigue regime at various
           displacement amplitudes and rates

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      Authors: Mohammad Azadi, Mohsen Alizadeh, Seyed Mohammad Jafari, Amin Farrokhabadi
      Abstract: Polymers and Polymer Composites, Ahead of Print.
      In the present article, acoustic emission signals were utilized to predict the damage in polymer matrix composites, reinforced by carbon fibers, in the low-cycle fatigue regime. Displacement-controlled fatigue tests were performed on open-hole samples, under different conditions, at various displacement amplitudes of 5.5, 6.0, 6.5 and 7.0 mm and also under various displacement rates of 25, 50, 100 and 200 mm/min. After acquiring acoustic emission signals during cycles, two characteristic parameters were used, including the energy and the cumulative energy. Obtained results implied that the energy parameter of acoustic emission signals could be used only for the macroscopic damage, occurring at more than 65% of normalized fatigue cycles under different test conditions. However, the cumulative energy could properly predict both microscopic and macroscopic defects, at least two failure types, including matrix cracking at first cycles and the fiber breakage at last cycles. Besides, scanning electron microscopy images proved initially such claims under all loading conditions.
      Citation: Polymers and Polymer Composites
      PubDate: 2021-01-06T03:59:51Z
      DOI: 10.1177/0967391120985709
       
 
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