for Journals by Title or ISSN
for Articles by Keywords
help
Journal Cover Journal of Applied Polymer Science
  [SJR: 0.578]   [H-I: 127]   [134 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0021-8995 - ISSN (Online) 1097-4628
   Published by John Wiley and Sons Homepage  [1589 journals]
  • Effect of POSS-grafted titanium dioxide on the electrical and thermal
           properties of LDPE/TiO2 polymer nanocomposite
    • Authors: Tung Tran Anh; Michel Fréchette, Éric David, René Veillette, Patricia Moraille
      Abstract: Two types of nanocomposites have been fabricated by a ball-milling technique. The first type consists of untreated titanium dioxide (TiO2) incorporated into low-density polyethylene (LDPE). For the second one, TiO2 filler chemically treated with trisilanol phenyl–polyhedral oligomeric silsesquioxane (TP–POSS) as compatibilizing agent was ball-milled with LDPE. All specimens were tested by microstructure analysis and thermal, dielectric characterization techniques. Microstructure analysis by atomic force microscopy and scanning electron microscopy show clearly an increased dispersion in presence of POSS. Scanning electron microscopy even shows the formation of a particular structure due possibly to interactions between functionalization. It was observed that the modification of the surface of TiO2 by the POSS decreased the dielectric loss. All nanocomposites containing treated TiO2 revealed an improvement in thermal conductivity, with the most distinct value of 19% in case of LDPE containing 5 wt % treated TiO2. The incorporation of TiO2 fillers seems to reduce the dielectric breakdown strength of the nanocomposites. However, nanocomposites containing 3 and 5 wt % treated TiO2 have exhibited a slightly enhancement in dielectric breakdown strength up to 5%. The improvement in surface resistance to partial discharge was found in all nanocomposites specimens, especially for both types of composite containing 7 wt % untreated and treated TiO2. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46095.
      PubDate: 2017-12-05T04:40:37.905671-05:
      DOI: 10.1002/app.46095
       
  • Research of phenolic crosslinker gel for profile control and oil
           displacement in high temperature and high salinity reservoirs
    • Authors: Jichao Fang; Jianhai Wang, Quanyi Wen, Sisi Fang, Xiaoqing He, Yan Ma, Yining Wu, Caili Dai
      Abstract: To further enhance oil recovery of high temperature and high salinity reservoir at Tahe Oilfield, field test results from profile control and oil displacement of gel were carried out in this article. Static and dynamic evaluations were performed through gel strength code method, environment scanning electron microscope, and physical simulation experiment devices. The field test results show that, under the conditions of high temperature (100.8 °C) and salinity (19.8 × 104 mg/L), the stable gel system was formed with gelling time range from 26 to 45 h, gel strength ranging from E to H, and dehydrating amount lower than 3.0% after ageing 60 days. Meanwhile, the microstructure is very stable. When the permeability and gel strength ranges from 0.212 to 0.970 μm2 and E to H, respectively, the plugging ratio is larger than 85%, and the plugging performance becomes better with the increase of permeability or gel strength. Due to the profile improvement rate of 99.8% and the oil recovery up to 28.5%, profile control and oil displacement technology of gel can effectively promote fluid diverting. The water cut reduced from 95.2% to 89.0% during field test carried out in Tahe Oilfield, which means that profile control and oil displacement technology of gel could stabilize oil production by water control effectively. Also, this technology has a wide application prospective that provides with strong technical support for further enhanced oil recovery in high temperature and high salinity reservoirs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46075.
      PubDate: 2017-12-05T04:40:31.158827-05:
      DOI: 10.1002/app.46075
       
  • Comparative mucoadhesive study of hyaluronic acid-based conjugates on
           different mucosae
    • Authors: Flavia Laffleur
      Abstract: The incentive of this study was to provide a detailed mucoadhesive comparison on adhesive properties on diverse mucosal surfaces such as nasal, buccal, and vaginal mucosa, respectively. Mucoadhesive hyaluronic acid–cysteine ethyl ester (HA–SH) conjugate was synthesized by the anchorage of sulfhydryl groups (SH) on the polymeric backbone of HA via amide bond formation between the carboxylic acid moieties of hyaluronic acid and sulfhydryl groups of cysteine ethyl ester. Histology assay in terms of alcian blue staining was performed on mucosal tissue in order to evaluate the potential impact on viability. The proficiency of water uptake was studied in various simulated body fluid. Moreover, mucoadhesive assays based on rotating cylinder, total work of adhesion, and maximum detachment force were carried out on various mucosae. The findings revealed in presence of 2.7-, 2.6-, and 1.25-fold improvement in swelling behavior in comparison to unmodified HA on nasal, buccal, and vaginal mucosa. Furthermore, mucoadhesive studies showed a 3.2-, 2.6-, 2.6-fold more extended residence time on nasal, buccal, and vaginal in presence of HA–SH in comparison to unmodified HA, respectively. Taken together, the comprehensive mucoadhesive study serve as guidance in the development of mucoadhesive drug delivery systems for versatile application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46071.
      PubDate: 2017-12-05T04:40:27.287813-05:
      DOI: 10.1002/app.46071
       
  • Layer-by-layer fabrication of nacre inspired epoxy/MMT multilayered
           composites
    • Authors: Sadia Batool; Rohama Gill, Muhammad Arshad, Humaira Masood Siddiqi, Shahid Saeed Qureshi
      Abstract: The organic–inorganic hybrid multilayered composites are prepared using a unique combination of poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER), amino modified montmorillonite (NH2-MMT), and polyethyleneimine (PEI). This tricomponent composite multilayer PEI(CNER/NH2-MMT/PEI)n deposited via layer-by-layer technique is based upon synergistic combination of covalent and hydrogen bonding. The growth of multilayer was monitored using UV–vis spectroscopy and ellipsometry. When subjected to optical analyses, the prepared multilayered composite films revealed profound optical transmittance ∼83%–87%. The surface morphological analysis by atomic force microscopy and scanning electron microscopy revealed uniform arrangement of organic–inorganic components with relative increase in intensity of elements (C, N, O, Si) as confirmed by X-ray photoelectron spectroscopy studies. The multilayered composites possess 1.99 GPa hardness making them potential candidate for a number of applications where mechanical strength is desired. Moreover, significant resistance against alkaline and organic solvents at minimal deterioration of circa 0.12% has also been observed for the prepared films. The epoxy clay based thin films being robust, scratch resistant, hydrophilic, chemically inert, and mechanically strong are potential candidates for advanced environmental applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46079.
      PubDate: 2017-12-03T10:57:05.880846-05:
      DOI: 10.1002/app.46079
       
  • Low-viscosity and soluble phthalonitrile resin with improved
           thermostability for organic wave-transparent composites
    • Authors: Zuoqiang Wu; Nan Li, Jianhua Han, Chenghao Wang, Kuanyu Yuan, Qiang Zeng, Jinyan Wang, Xigao Jian
      Abstract: High processing viscosity and poor solubility limit the application of heterocyclic polymers for fabricating organic wave-transparent composites for aerospace applications. In this paper, a novel resin, poly(phthalazinone ether bisphenol fluorene) encapped with phthalonitrile (PPEBF-Ph), was synthesized and used as the matrix. Biphenol-based phthalonitrile monomer BP-Ph was also synthesized and blended with PPEBF-Ph to further lower the processing viscosity. Solubility tests showed that the resin was soluble in dimethylformamide, N,N-dimethyl acetamide, N-methylpyrrolidone, dimethyl sulfoxide, chloroform, and other solvents. Differential scanning calorimetry and rheological studies revealed that the mixed resins exhibited low processing viscosity and a wide processing window below the gel temperature. Thermogravimetric analysis indicated that the cured resins were stable below 510–530 °C under nitrogen atmosphere after 6 h of curing (decreased by 40–60% compared with previous reports on phthalonitrile resin). In air, the char yields of the resins reached 20–30% when heated at 800 °C. The composites were reinforced by a quartz fiber cloth and exhibited a dielectric constant of 2.94–3.27 in an electromagnetic field with frequency ranging from 8 to 18 GHz. Retention of the bending modulus exceeded 70% at 400 °C according to dynamic mechanical analysis, indicating excellent mechanical stability was obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45976.
      PubDate: 2017-12-03T10:56:55.261548-05:
      DOI: 10.1002/app.45976
       
  • Enhanced mechanical properties and fire retardancy of polyamide 6
           nanocomposites based on interdigitated crystalline
           montmorillonite–melamine cyanurate
    • Authors: Min Zhao; Deqi Yi, Rongjie Yang
      Abstract: Polyamide 6 (PA6)–montmorillonite (MMT)–melamine cyanurate (MCA) nanocomposites were prepared by the incorporation of interdigitated crystalline MMT–MCA. Their morphologies were assessed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal stability measurement by thermogravimetric analysis, mechanical properties measurement by tensile tests, and fire retardancy measurement by limiting oxygen index testing and vertical burning testing (UL-94). The results indicate that MMT–MCA was homogeneously nanodispersed in PA6. Compared with PA6–MCA, the PA6–MMT–MCA nanocomposites showed enhanced thermal stability. The mechanical properties and fire retardancy show that the PA6–MMT–MCA nanocomposites with 5 wt % total loading of MMT–MCA reached UL-94 V-2 rating (3.2 mm) and significantly increased the tensile strength of PA6 up to 24.8 % with only 1 wt % MMT in PA6. Through the control the weight ratio of MMT and MCA in MMT–MCA, the Young's modulus of PA6 could be adjusted in a very wide range (300–1100 MPa) because of the dual role of the rigid MMT and nonrigid MCA layers. The reinforced mechanism of the mechanical properties was also investigated. Consequently, the PA6–MMT–MCA nanocomposites with a good nanodispersing ability, improved thermal stability, excellent mechanical properties, and good flame retardancy were obtained and could provide broad prospects for wider applications for PA6 materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46039.
      PubDate: 2017-12-03T10:56:42.741841-05:
      DOI: 10.1002/app.46039
       
  • Synthesis of phospholipidated β-cyclodextrin and its application for
           flame-retardant poly(lactic acid) with ammonium polyphosphate
    • Authors: Yan Zhang; Pengyu Han, Zhengping Fang
      Abstract: In this study, phospholipidated β-cyclodextrin (PCD) was obtained by the condensation between β-cyclodextrin and phenyl phosphonic acid dichloride, which was characterized by Fourier transform infrared (FTIR) spectra, 1H-NMR, and thermogravimetric analysis (TGA). The thermal stability and flame retardancy of the poly(lactic acid) (PLA) blends [PLA–ammonium polyphosphate (APP)–PCD] were measured by TGA coupled to FTIR spectroscopy, vertical burning test (UL-94), limiting oxygen index (LOI), and cone calorimetry tests. The results show that the mass ratio and loading amount of APP and PCD affected the properties of PLA. When the loading of APP and PCD was 30 wt % and the mass ratio of APP to PCD was 5:1, the highest LOI value of 42.6% (that of neat PLA was 19.7%) and a UL-94 V0 rating were achieved, and the reduction of the total heat release was greater than 80%. Even when the total amount of APP and PCD was decreased to 20 wt % with the same mass ratio, the flame-retardant PLA still can achieved a UL-94 V0 rating. The improved performance was explained by the formation of an intumescent, continuous, contact char layer. Moreover, the reaction between APP and PCD contributed to the improvement of the thermal stability of the char residue. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46054.
      PubDate: 2017-12-03T10:56:29.195161-05:
      DOI: 10.1002/app.46054
       
  • Enhancement of the mechanical properties and thermostability of poly(vinyl
           alcohol) nanofibers by the incorporation of sodium chloride
    • Authors: Yan Shi; Yuming Zhao, Xinhua Li, Dongpeng Yan, Ding Cao, Zhifeng Fu
      Abstract: The mechanical properties and thermostability of poly(vinyl alcohol) (PVA) nanofiber mats have been obviously improved by the incorporation of sodium chloride (NaCl). The tensile properties including tensile strength and modulus of membranes with an addition of 1.0 wt % NaCl increased from 2.51 to 4.22 MPa and 33.0 to 176.30 MPa, respectively, more than 160 and 700% of those of the electrospun pure PVA membranes. Moreover, thermogravimetric analysis showed that the initial decomposition temperature (Ti) and the half decomposing temperature (T50%) of PVA nanofibers with the addition of NaCl were at least 26 and 59 °C higher than that of pure PVA nanofibers, respectively, indicating a strong interaction between the PVA and the salt ions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45981.
      PubDate: 2017-12-03T10:56:22.149979-05:
      DOI: 10.1002/app.45981
       
  • Melt-processable and self-healing poly(vinyl alcohol) elastomer containing
           diol groups in the side chain
    • Authors: Fayong Li; Hesheng Xia
      Abstract: A 3-amino-1,2-propane diol functionalized poly(vinyl alcohol) elastomer (PVA–COO–AP) with melt processability and self-healing properties was prepared by chemical graft modification, that is, a poly(vinyl alcohol) (PVA) carboxylation and carbodiimide reaction. Unlike that of conventional PVA modifiers, the incorporation of diol groups in the 3-amino-1,2-propane diol molecules onto PVA chains reduced the breaking of intrinsic hydrogen-bonding interactions of PVA because of the formation of new hydrogen bonds between the diol groups and the hydroxyl groups of PVA. PVA–COO–AP possessed a lower melting temperature and a higher decomposition temperature than PVA; this enabled the melt processing of PVA. The PVA–COO–AP samples prepared by compression molding exhibited excellent flexibility and elasticity, and the samples with a lower glass-transition temperature below ambient temperature could be self-healed because of the existence of dynamic hydrogen bonds. AP–COO–AP is believed to have potential applications in the fields of fibers and biomedical membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46050.
      PubDate: 2017-12-03T10:56:15.716218-05:
      DOI: 10.1002/app.46050
       
  • Toughening polylactide with epoxidized styrene–butadiene impact resin:
           Mechanical, morphological, and rheological characterization
    • Authors: Yanshai Wang; Zhiyong Wei, Yang Li
      Abstract: Styrene–butadiene impact resin (SBC) was chosen as the toughening agent to improve the tensile toughness of polylactide (PLA). Epoxidized SBC (ESBC) with different epoxidation degree were prepared by epoxidation using in situ peroxoformic acid method and a series of PLA/SBC(ESBC) blends were prepared by melt blending. The elongation at break of the PLA/ESBC blends was greatly improved, which was reflected in the slight decrease in the tensile strength and tensile modulus. Moreover, the tensile strength and tensile modulus were not significantly affected by the epoxidation degree of ESBC. For example, the incorporation of ESBC28.8% (30 wt %) to PLA caused an obvious increment of elongation at break from 3.5% of pure PLA to 305.0%, while the tensile modulus and tensile strength decreased to 80 and 78% of pure PLA, respectively. Scanning electron microscopy observations of cryo-fractured surface morphology and particle size analysis demonstrated that the compatibility of the PLA/ESBC blends was improved significantly compared to PLA/SBC blend. PLA/ESBC(70/30) blends exhibited shear-thinning behavior over the range of the studied shear rate. With an increase in shear rate, the non-Newtonian index of the blends decreased gradually. Furthermore, the flow behavior of PLA/ESBC(70/30) blends was more sensitive to the shear rate than pure PLA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46058.
      PubDate: 2017-12-03T10:56:10.387476-05:
      DOI: 10.1002/app.46058
       
  • A versatile radiochromic dosimeter for low-medium gamma radiation and its
           application to food irradiation
    • Authors: Franceline Aparecida Lopes; Giovana Ribeiro Ferreira, Marcella Rocha Franco, Thiago Schimitberger, Luiz Oliveira de Faria, Rodrigo Fernando Bianchi
      Abstract: This article presents a novel radiochromic film for selective detection of low-medium (0–10 kGy) gamma radiation (60Co) doses. This dosimeter is based on a printed fluorescent multilayer structure comprising a paper substrate having layers of copper phthalocyanine (DY220) (a green emitter material) on the bottom, and layers of poly[2-methoxy-5(2′-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) (a green-light absorber, red emitter, and radiation sensitive polymer) on the top. The effect of gamma radiation on the optical properties of DY220/MEH-PPV was described: it was observed as a strong correlation between radiation dose and fluorescent, color coordinates for CIE (1931) chromatic diagram, and Pantone color reference of the dosimeter. The rate of these changes can be altered by manipulation of top–bottom layers to represent easily the radiation dose to be determined in a wide range. This versatile dosimeter has many uses in the field of food radiation for monitoring, quality assurance, and control of the gamma radiation process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45729.
      PubDate: 2017-12-03T10:56:03.20614-05:0
      DOI: 10.1002/app.45729
       
  • Recyclable, shape-memory, and self-healing soy oil-based polyurethane
           crosslinked by a thermoreversible Diels–Alder reaction
    • Authors: Kaiwen Zheng; Yazhou Tian, Mengjin Fan, Junying Zhang, Jue Cheng
      Abstract: The recyclable, shape-memory, and self-healing soy oil-based polyurethane (S-PU) networks were constructed by the thermoreversible Diels–Alder (DA) reaction between S-PU (sealed with furfuryl alcohol) and 1,5-bis(maleimido)-2-methylpentane. The DA and retro-DA reactions between furan and maleimide were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, solubility, and recycle testing. Moreover, the shape-memory properties of the S-PU networks were studied by qualitative recovery testing and quantitative cyclic tensile testing. Furthermore, the self-healing properties of S-PU networks were confirmed by cut, scratch, and tensile testing. The results showed that, compared to the traditional S-PU, the novel S-PU prepared in this work was recyclable and self-healing. And although both of them have shape-memory effect, the novel S-PU has a higher shape fixed rate and shape recovered rate than the traditional S-PU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46049.
      PubDate: 2017-12-03T10:55:57.607537-05:
      DOI: 10.1002/app.46049
       
  • Sustainable bionanocomposite from d,l-lactide/δ-valerolactone triblock
           and bionanowhiskers: Preparation, characterization, and properties
    • Authors: Nibedita Kasyapi; K. Dinesh Kumar, Anil K. Bhowmick
      Abstract: Bionanocomposites were prepared using d,l-lactide–δ-valerolactone–d,l-lactide triblock and unmodified and modified cellulose nanowhiskers (CNs) at different loadings (0, 2, 4, 8 wt %). Poly(δ-valerolactone) chains were grafted on CNs for modification. These were characterized by various techniques. The broadening of OH (hydroxyl) stretching region and the presence of low-intensity peaks at 1064 cm−1 for CO/CC stretching vibration and 1426 cm−1 for bending vibration of CH2 group, were evident in Fourier transform infrared spectra of the nanocomposites. The increase in crystallinity was noticed as the amount of nanowhiskers was increased. The nanowhiskers having the width in the range of 80–300 nm were uniformly dispersed in the triblock matrix. The tensile strength and modulus increased by 130% and 50% respectively at 8 wt % of filler loading. The storage modulus, loss modulus, complex viscosity, and tan δ values increased with increased filler loading. Further improvement in mechanical properties was observed with the modified CNs. The modulus mapping from atomic force microscopy confirmed the effective reinforcement behavior of the nanowhiskers. Scaffold fabrication using the bionanocomposite exhibited porous nature, having a homogeneous dispersion of CNs on the surface of the scaffold. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay confirmed the suitability of the composite material for scaffold application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46035.
      PubDate: 2017-12-03T10:55:39.401919-05:
      DOI: 10.1002/app.46035
       
  • A new thermoset for separation of polystyrene and naphthalene in
           preparative chromatography
    • Authors: Wesley de Oliveira Rosa; Vagner R. Botaro
      Abstract: Many research groups in recent years have demonstrated the importance of obtaining new materials and reducing environmental impact. In this context, the chemical modification of cellulose and its derivatives has received much attention. This study synthesized cellulose acetate gel (CAMDIH) obtained through the modification of cellulose acetate (CA) with a degree of substitution of 2.5, by crosslinking reactions using 4,4′-diphenylmethane diisocyanate in homogeneous medium. The formation of crosslinks were observed by the presence of Fourier transform infrared spectroscopy absorption bands at 3046 and 864 cm−1, which correspond to the absorption of aromatic groups associated with the incorporation of 4,4′-diphenylmethane diisocyanate in the CA structure. The potential applications of the gel as a stationary phase were tested using column chromatography in the fractionation and separation of standard solutions of polystyrene and naphthalene. The findings showed the effectiveness of the gel as a stationary state in the separation of mixture compounds. Furthermore, the study found that CAMDHI is an innovative material when considering its simple synthesis and the low costs involved in the process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46063.
      PubDate: 2017-12-03T10:55:30.001125-05:
      DOI: 10.1002/app.46063
       
  • One-pot synthesis of cobalt-incorporated polyglycerol ester as an
           antimicrobial agent for polyurethane coatings
    • Authors: Bing Wei Chua; Choy Sin Lee, Wen Huei Lim, Mallikarjuna Rao Pichika
      Abstract: Cobalt-incorporated poly(glycerol ester) (Co–PGE) was synthesized by the polycondensation of glycerol and adipic acid followed by the reaction with cobalt(II) hydroxide under solvent-free and noncatalyzed one-pot synthesis conditions. The reaction was monitored through the acid value and hydroxyl value determination. The chemical structure and molecular weight of the poly(glycerol ester) (PGE) and Co–PGE were characterized by Fourier transform infrared spectroscopy, 13C-NMR, gel permeation chromatography, and inductively coupled plasma mass spectrometry. Co–PGE with a 59.3% degree of branching was incorporated with up to 5.0% w/w cobalt, and it exhibited antimicrobial inhibition against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in a broth microdilution study. Polyurethane (PU) coatings were prepared by the blending of 0.5–35% w/w Co-PGE containing with 5% w/w of cobalt with blank PGE, poly(ethylene glycol) with a molecular weight of 6000, poly(caprolactone diol) with a molecular weight of 2000, and additives to react with isophorone diisocyanate. The prepared PUs demonstrated mild to high antimicrobial activities against E. coli, S. aureus, Bacillus subtilis, and C. albicans strains in a disc diffusion test. PU prepared with 0.5% w/w Co–PGE showed a mild inhibition activity against S. aureus, and PU prepared with 10% w/w Co–PGE demonstrated a high inhibition activity against C. albicans. This study demonstrated that value-added Co–PGE synthesized from glycerol has the potential as an antimicrobial agent for polymer coatings in biomedical devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46045.
      PubDate: 2017-12-03T10:55:24.084846-05:
      DOI: 10.1002/app.46045
       
  • Compressive response of PMMA microcellular foams at low and high strain
           rates
    • Authors: Ruizhi Zhang; Lianmeng Zhang, Jian Zhang, Guoqiang Luo, Dawu Xiao, Zhenfei Song, Meijuan Li, Yuanlu Xiong, Qiang Shen
      Abstract: Microcellular foams are widely applied in various applications in both civil and military applications for barriers and energy absorption materials. Poly(methyl methacrylate) microcellular foams were fabricated via supercritical foaming method. Field emission scanning electron microscopy, differential scanning calorimetry, and mechanical test machine were used to visualize the foam structure and test the quasi-static compression properties. Moreover, Split Hopkinson Bar (SHPB) setups were adopted to explore the dynamic compression properties. The experimental results show that the microcellular foams have homogeneous cell size distribution and exhibit superior compressive behavior at both quasi-static and high strain rates. The mechanical properties depend on both foam density and strain rate. Strain rate effects are clearly observed. At quasi-static strain rate and 7500 S−1 regime, cell wall bucking and folding are the main failure mechanism. However, at high strain rate regime, softening phenomenon is observed. By roughly calculating the energy absorbed and the temperature rise, the temperature of the foams will rise up to as high as 130 °C after conducting high strain rate compression, and it is postulated that the generated heat will destroy the cell structure of the foams. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46044.
      PubDate: 2017-12-01T07:56:31.357022-05:
      DOI: 10.1002/app.46044
       
  • Thermomechanical and electroactive behavior of a thermosetting
           styrene-based carbon black shape-memory composite
    • Authors: Xin Lan; Liwu Liu, Yanju Liu, Jinsong Leng
      Abstract: A thermosetting styrene-based shape memory polymer (SMP) filled with nanoscale (30 nm) carbon black are prepared to reinforce the thermomechanical performances and realize the high-efficient electronic actuation at macro scale due to the carbon–carbon network morphology at nano/micro scale. The elastic modulus of this thermosetting SMP composite is significant strengthened and can maintain at 1–2.5 GPa at around the room temperature, which is suitable for used as a structural material. The electronic resistivity decreases sharply at a quite low percolation threshold range (2–5%), and maintains at a relatively low and stable level of electronic resistivity. Furthermore, the electronic resistivity also exhibits relative stability in terms of the resistivity–temperature–time relationship and the evolution of resistivity upon heating–cooling cycles. This shape memory styrene-based composite is suitable to be used as an electroactive functional material in realistic engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45978.
      PubDate: 2017-12-01T07:56:17.945172-05:
      DOI: 10.1002/app.45978
       
  • Highly effective organometallic-mediated radical polymerization of vinyl
           acetate using alumina-supported Co(acac)2 catalyst: A case study of
           adsorption and polymerization
    • Authors: Mohammad Ali Semsarzadeh; Alireza Sabzevari
      Abstract: An alumina support system for cobalt(II) acetylacetonate (Co(acac)2) catalyst was studied for the cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc). We report a simple but efficient technique to produce this supported catalysts through the adsorption of Co(acac)2 on the surface of alumina particles. Moreover, kinetic and thermodynamic study of Co(acac)2 adsorption on the alumina support were conducted and the influence of effective parameters were investigated. It was found that using alumina-supported Co(acac)2 for radical polymerization of VAc yields polymers with controlled molecular weight, narrow molecular weight distribution, and high purity. For the alumina-supported CMRP, changing the polymerization mechanism and domination of termination pathway compared to degenerate transfer pathway resulted in a 2.5 times increase in polymerization rate (kap) and a drop in induction time while maintaining a good control of the VAc polymerization. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46057.
      PubDate: 2017-12-01T07:56:04.945592-05:
      DOI: 10.1002/app.46057
       
  • Multilayer coextrusion of graphene polymer nanocomposites with enhanced
           structural organization and properties
    • Authors: Yuqing Gao; Olivier T. Picot, Wei Tu, Emiliano Bilotti, Ton Peijs
      Abstract: A potential advantage of platelet-like nanofillers as nanocomposite reinforcements is the possibility of achieving two-dimensional (2D) stiffening through planar orientation of the platelets. Forced assembly by multilayer coextrusion, which enables the in-plane orientation of platelet-like fillers in alternating layers, was used in this work to produce poly(lactic acid) (PLA)/graphene multilayer films. These films exhibited a multilayer structure made of alternating layers of neat PLA and PLA containing graphite nanoplatelets (GNPs). Electron microscopy revealed information on the orientation of the individual GNPs. X-ray diffraction results indicated that the thickness of the individual GNPs was reduced during the multilayer coextrusion process. A significant reinforcement of 120% at an overall GNP loading of 1 wt % in PLA was achieved. This high effective reinforcement was attributed to the high degree of planar alignment, improved dispersion and exfoliation and increased aspect ratio of the GNPs in the composite layers after multilayer coextrusion. Improved water vapor barrier properties were also achieved as a result of the highly organized 2D nanofillers in the multilayer films. These industrial scalable multilayer nanocomposite films open up possibilities for lightweight and strong packaging materials for food and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46041.
      PubDate: 2017-12-01T07:55:59.335559-05:
      DOI: 10.1002/app.46041
       
  • Chitosan/MCM-41 nanocomposites for efficient beryllium separation
    • Authors: Rania E. Morsi; Mohamed A. Elsherief, M. Shabaan, M. Z. Elsabee
      Abstract: Chitosan nanoparticles (Ch NPs) with individual particles 10–30 nm in size and average aggregate sizes of 240 nm were prepared via ionic gelation. Ordered mesoporous Mobil Composition of Matter No. 41 (MCM-41) with a surface area of 1590 m2/g was prepared via a sol–gel method. The nanocomposites were prepared via the in situ dispersion of MCM-41 in chitosan followed by ionic gelation with a multivalent anion to produce MCM-41-impregnated Ch NPs or via the mixture of dispersed MCM-41 with preprepared Ch NPs to produce Ch NPs supported on MCM-41. The beryllium-uptake efficiency was studied with different pH values, contact times, and initial Be(II) concentrations. The maximum achieved uptake efficiencies of the nanocomposites (95 and 96%) were superior to that of MCM-41 (38%) and higher than that of Ch NPs (90%). The nanocomposite formulas facilitated post-treatment separation while maintaining a high beryllium-uptake efficiency. The Be(II)-uptake process for all of the materials followed the pseudo-second-order kinetic model and both the Langmuir and Freundlich isotherms. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46040.
      PubDate: 2017-12-01T07:55:49.29946-05:0
      DOI: 10.1002/app.46040
       
  • Kinetic studies of POSS–DGEBA precursors derived from monoamine
           functional POSS using dynamic dielectric sensing and nuclear magnetic
           resonance
    • Authors: Amit K. Sharma; Mohammad K. Hassan, Jianwei Tu, Kenneth A. Mauritz, Jeffrey S. Wiggins
      Abstract: Incorporation of pre-reacted monofunctional polyhedral oligomeric silsesquioxane (POSS)–epoxy adducts dramatically improves dispersion of POSS in epoxy–amine networks. The relationship between reaction kinetics and mechanism for formation of POSS–epoxy adducts versus reaction temperature was investigated. Reactivities of epoxy–monoamine functional POSS molecules were determined using in situ reaction monitoring by dynamic dielectric sensing and 29Si NMR spectroscopy. The amine-functional POSS–epoxy isothermal reaction showed reduced reactivity due to reduced molecular mobility, that is, diffusion limitations. Kinetic parameters were determined by fitting 29Si NMR data to the model of Kamal that was extended to include diffusion. Fitting of this model to experimental data showed very good agreement over the entire conversion range for pre-reaction between amine-functionalized POSS and epoxy. An autocatalytic mechanism, the same as that for the neat epoxy–amine systems, was indicated. Gel permeation chromatography, scanning electron microscopy and transmission electron microscopy were used to investigate molecular weight evolution and morphology of final networks cured by 4,4′ diaminodiphenyl sulfone using pre-reacted POSS–epoxy adducts. POSS aggregate size decreased with increased pre-reaction temperature; more homogenous POSS dispersion was observed with higher pre-reaction temperature. Dynamic mechanical analysis demonstrated that Tg of composites decreased slightly compared to that of the neat matrix and there appeared to be little change in microstructural heterogeneity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45994.
      PubDate: 2017-12-01T07:55:41.298172-05:
      DOI: 10.1002/app.45994
       
  • Conformational changes after foaming in a protein-based thermoplastic
    • Authors: Chanelle Gavin; Mark C. Lay, Casparus J. R. Verbeek
      Abstract: Novatein is a biopolymer produced from blood meal and can be foamed for use as a packaging material. The effect of foaming on protein ordered structures such as α-helices and β-sheets was investigated using synchrotron Fourier transform infrared (FTIR). Foaming caused a reduction in ordered structures due to an increase in random coils. FTIR also revealed a higher proportion of plasticizer (triethylene glycol, TEG) and β-sheets toward the surface of enclosed bubbles. Increased TEG will assist foaming with greater plasticization aiding nucleation, while β-sheets contribute to bubble stabilization. These structural changes occur as foaming takes place close to the degradation temperature of Novatein, and coincide with melting of α-helices and/or β-sheets. A more amorphous polymer is therefore produced which is subsequently easier to foam due to its increased elasticity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46005.
      PubDate: 2017-12-01T07:55:32.036309-05:
      DOI: 10.1002/app.46005
       
  • Fully bio-based polyesters derived from 2,5-furandicarboxylic acid
           (2,5-FDCA) and dodecanedioic acid (DDCA): From semicrystalline
           thermoplastic to amorphous elastomer
    • Authors: Zhen Jia; Jinggang Wang, Liyuan Sun, Jin Zhu, Xiaoqing Liu
      Abstract: A serials of fully bio-based poly(ethylene dodecanedioate-2,5-furandicarboxylate) (PEDF) were synthesized from Dodecanedioic acid (DDCA), 2,5-Furandicarboxylic acid (2,5-FDCA), and ethylene glycol through a two-step procedure consisted of transesterification and polycondensation. After their chemical structures were confirmed by Nuclear Magnetic Resonance and Fourier Transform Infrared Spectroscopy, their thermal, mechanical, and biodegradation properties were investigated in detail. Results showed that the chemical composition of PEDFs could be easily controlled by the feeding mole ratio of DDCA to FDCA and they possessed the characteristic of random copolyester with the intrinsic viscosity ranged from 0.82 to 1.2 dL/g. With the varied mole ratio of DDCA to FDCA, PEDFs could be changed from semicrystalline thermoplastic to the completely amorphous elastomer, indicated by the elongation at break ranged from 4 for poly(ethylene 2,5-furandicarboxylate) to 1500% for amorphous PEDF-40. The amorphous PEDF-30 and PEDF-40 showed satisfactory shape recovery after cyclic tensile test, which was the typical behavior for elastomer. Enzymatic degradation test indicated that all the PEDFs were biodegradable and the degradation rate was heavily affected by their chemical compositions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46076.
      PubDate: 2017-11-29T08:46:13.028585-05:
      DOI: 10.1002/app.46076
       
  • Surface functionalized nanocellulose as a veritable inclusionary material
           in contemporary bioinspired applications: A review
    • Authors: Kwok-Mern Chin; Sam Sung Ting, Hui Lin Ong, Mf Omar
      Abstract: The past few decades have seen extraordinary gain in interest for bio-based products, driven by the intensifying call of the society for petrochemical material replacement and developing materials with next-to-no environmental impact. Cellulose, which is an abundantly available “green” material, can be derived from plant fibers and tailored for a plethora of possible uses where it can be used as a substrate or as a filler material. However, emerging technologies and product advancements necessitate the search for materials that are small, biodegradable, lightweight, and strong. Nanocellulose, which can be obtained through as mechanical and chemical production methods with tensile strength and Young's modulus of up to 0.5 and 130 GPa, respectively, proves to be the answer that they were looking for. However, the inherent hydrophilic nature of nanocellulose limited its potential widespread application. Surface modifications of nanocellulose to alter and diminish its hydrophilicity were done to address the aforementioned issues. In this article, we had reviewed on different types of surface modifications and their resulting impact on the properties of nanocellulose and their effect on polymer composites. The importance of nanocellulose in emerging applications such as biosensor, nanoremediation, papermaking, and automotive as well as the current state of the industry and the commercialization progress of nanocellulose were also discussed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46065.
      PubDate: 2017-11-29T08:45:46.698374-05:
      DOI: 10.1002/app.46065
       
  • Thermoreversible rheological responses of biscarbamates and tricarbamates
           in uncured epoxy composite pastes caused by their self-assembly in an
           epoxy matrix
    • Authors: Ming Zhang; Mingqing Chen, Zhongbin Ni
      Abstract: We investigated the rheological behaviors of diglycidyl ether of bisphenol A (epoxy resin) composite pastes with fumed SiO2, biscarbamates, and tricarbamates with the same terminal alkyl chains of C16, respectively. The rheological measurement results show that the rheological responses of both carbamates in the epoxy composite pastes were stronger than that of fumed silica at the same concentrations, especially at low concentrations, and the rheological behaviors of the epoxy composites with them were thermally reversible and concentration dependent. IR, thermal, differential scanning calorimetry, and polarized microscopic analyses demonstrated that their different excellent rheological responses in epoxy composite pastes came from their different self-assemblies in the epoxy matrix, which were caused by the different intermolecular interactions, mainly including hydrogen-bonding and van de Waals interactions, and the intermolecular interactions for carbamates were closely related to their molecular structures. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46032.
      PubDate: 2017-11-29T08:45:38.588196-05:
      DOI: 10.1002/app.46032
       
  • Biodegradable polymeric injectable implants for long-term delivery of
           contraceptive drugs
    • Authors: Ohan S. Manoukian; Michael R. Arul, Naseem Sardashti, Teagan Stedman, Roshan James, Swetha Rudraiah, Sangamesh G. Kumbar
      Abstract: Development of injectable, long-lasting, contraceptive drug delivery formulations, and implants are highly desired to avoid unplanned pregnancies while improving patient compliance and reducing adverse side effects and treatment costs. The present study reports on the fabrication and characterization of two levonorgestrel (LNG) microsphere injectable formulations. Poly(ɛ-caprolactone) (PCL) with 12.5% and 24% (w/w) LNG were fabricated into microspheres, measuring 300 ± 125 µm, via the oil-in-water (o/w) emulsion solvent evaporation technique. Formulations showed sustained drug release up to 120 days. FTIR, XRD, DSC, and TGA confirmed the absence of LNG chemical interaction with PCL as well as its molecular level distribution. The in vitro release of LNG was calculated to be Fickian diffusion controlled and properly characterized. The inclusion of multiple elevated release temperatures allowed for the application of the Arrhenius model to calculate drug release constants and representative sampling intervals, demonstrating the use of elevated temperatures for accelerated-time drug release studies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46068.
      PubDate: 2017-11-29T02:30:57.922868-05:
      DOI: 10.1002/app.46068
       
  • Polymersome formation mechanism and formation rate in stirred-tank
           reactors
    • Authors: Sarah T. Poschenrieder; Marianne Hanzlik, Kathrin Castiglione
      Abstract: Uniform polymersomes (polymer vesicles) made of poly(2-methyloxazoline)15-b-poly(dimethylsiloxane)68-b-poly(2-methyloxazoline)15 (PMOXA15–PDMS68–PMOXA15) can be formed in miniaturized-stirred tank reactors by the aid of a recently published process. In this study, the occurring self-assembly mechanism was elucidated by using transmission electron microscopy. Subsequent to the initial formation of small spherical micelles and the following fusion to worm-like micelles, two simultaneously occurring pathways, describing the transformation of further intermediate structures to the desired vesicles, were found. The resulting particle increase was followed by dynamic light scattering. Thus, the vesicle formation rate was judged by the linear increase of the particle diameter over time. While temperature showed no influence, higher initial polymer concentrations and lower final solvent concentrations accelerated the polymersome formation. Besides, the process was crucially dependent on the agitation speed. While spherical micelles did not transform into polymersomes when no stirring or too slow stirring is applied, the self-assembly process was accelerated by increasing the agitation speed. Uniform polymeric vesicles can be formed under vigorous stirring in stirred-tank reactors in short process times. In this study, the underlying mechanisms of vesicle formation were elucidated, showing that the polymer forms small micellar structures before undergoing two separate pathways to form the desired vesicular structures. The formation rate of the polymer vesicles was mainly dependent on the agitation speed but also on the polymer and solvent concentrations, highlighting the need for controlled formation conditions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46077.
      PubDate: 2017-11-29T02:30:46.268334-05:
      DOI: 10.1002/app.46077
       
  • Decorated-magnetic-nanoparticle-supported bromine as a recyclable catalyst
           for the oxidation of sulfides
    • Authors: Yanfang Hu; Weiqian Ma, Meilin Tao, Xueyan Zhang, Xiaohong Wang, Xiaoyu Wang, Li Chen
      Abstract: Herein, we present a strategy for supporting bromine as a catalyst for the oxidation of sulfides. In this strategy, branched poly(ethylene imine) was first decorated by magnetic oxide and then used to support liquid bromine to obtain solid polymeric bromine (M@PEI@Br) nanoparticles. Compared with free bromine, the stability of the M@PEI@Br nanoparticles improved obviously. The oxidation of thioanisole to methyl phenyl sulfoxide was chosen as a reaction model to evaluate the catalytic activity of the M@PEI@Br nanoparticles. All of the obtained results verify that the M@PEI@Br nanoparticles exhibited excellent catalytic efficiency and could accelerate the oxidation process under solvent-free conditions at room temperature; this highlighted the potential of decorated polymers to support active and unstable small-molecule organic catalysts. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46036.
      PubDate: 2017-11-29T02:30:27.769541-05:
      DOI: 10.1002/app.46036
       
  • White-light-emitting hybrid film from fluorescent hyperbranched poly(amido
           amine)
    • Authors: Wen Yang; Xiaomin Wang, Shengnan Wang, Wentao Hao
      Abstract: The flexible, strong, and tough white-light-emitting (WLE) hybrid films are highly demanded in large-scale displays, including TV sets, monitors, and electronic interactive devices. In this work, a kind of WLE hybrid film was fabricated from hyperbranched poly(amido amine) (HPAMAM) and nanoclay with the incorporation of riboflavin (VB2) and rhodamine B (RhB). The fluorescence emission of HPAMAM was partially absorbed and effectively transferred into green and red color, which combined into a bright white light with the residue blue fluorescence. Due to the alignment of nanoclay inside the HPAMAM matrix, in addition to the strong interaction among the HPAMAM molecules and that between HPAMAM and nanoclay, this hybrid film shows to be strong and tough. The mechanical strength is about 20 MPa and the elongation is about 30%. It is convinced that this hybrid film is promising in flexible large-scale displays. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46015.
      PubDate: 2017-11-28T07:07:28.662417-05:
      DOI: 10.1002/app.46015
       
  • Enhanced degradation properties of polypropylene integrated with iron and
           cobalt stearates and its synthetic application
    • Authors: Malini Subramaniam; Swati Sharma, Arun Gupta, Norhayati Abdullah
      Abstract: Synthetic plastic leads to environmental contamination, and a promising solution to this problem is to use prooxidants as fillers within them to speed up the photooxidation and thermooxidation processes. This makes plastics more susceptible to biodegradation. In this study, the degradation properties of the widely used polymer polypropylene (PP) were improved by integration with cobalt stearate (CoSt2) and iron stearate (FeSt3) as prooxidants with accelerating weathering degradation. The metal stearates were blended with PP in the concentration range 0.1–0.9% w/w. The properties of the blends were studied by mechanical properties testing, thermogravimetric analysis, differential scanning calorimetry, and water absorption measurement. We performed the degradation properties and thermooxidative studies by conducting an accelerated weathering test on PP–metal salt blends. Fourier transform infrared spectroscopy and scanning electron microscopy analysis of the samples before and after the accelerated weathering test were performed to study the extent of degradation in PP-based metal salt blends. The results indicate that the tensile strength was inversely proportional to the concentration of metal stearates, and the samples showed an increased degree in polymer crystallinity (PPFe5 > PPCo5), and this led to the degradation of PP in less time. CoSt2 predominantly enhanced the degradation of PP in comparison to FeSt3. Food containers and pots were constructed with the tailored polymers of PP in the injection-molding machine. Thus, metal-stearate-integrated polymers have great industrial potential to generate value-added products. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46028.
      PubDate: 2017-11-28T07:07:10.481805-05:
      DOI: 10.1002/app.46028
       
  • Synthesis of reusable silicone foam containing carbon nanotubes for oil
           spill remediation
    • Authors: Elpida Piperopoulos; Luigi Calabrese, Emanuela Mastronardo, Edoardo Proverbio, Candida Milone
      Abstract: The aim of this work is the synthesis of silicone foam containing carbon nanotubes (CNT) for oil spills remediation. The CNT silicone foams are obtained by foaming a solution of a silicone matrix with CNT filler (5.6 wt %) in presence of a Sn-based catalyst. Pristine and functionalized CNT have been used. All the obtained materials present a foam morphology with an open cell structure. Each foam is tested in four commonly used oils (kerosene, pump oil, naphtha, and crude oil). Among all, the foam filled with pristine CNT shows the highest sorption capacity (800 wt % in virgin naphtha) and an excellent reusability (up to 10 times). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46067.
      PubDate: 2017-11-28T07:06:58.135214-05:
      DOI: 10.1002/app.46067
       
  • Thermoresponsive and biocompatible poly(vinyl
           alcohol)-graft-poly(N,N-diethylacrylamide) copolymer: Microwave-assisted
           synthesis, characterization, and swelling behavior
    • Authors: Nuran Işıklan; Hacer Kazan
      Abstract: Novel thermoresponsive poly(vinyl alcohol)-graft-poly(N,N-diethylacrylamide) (PVA-g-PDEAAm) copolymers were prepared by microwave-assisted graft copolymerization using a potassium persulfate/N,N,N′,N′-tetramethylethylenediamine (KPS/TEMED) initiator system. The structures of PVA-g-PDEAAm copolymers were characterized by 1H-NMR, Fourier transform infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis, gel permeation chromatography, X-ray diffraction, and scanning electron microscopy. The effects of various process parameters on grafting were systematically studied: microwave power, KPS, monomer and PVA concentrations, and ultraviolet irradiation. Under optimal conditions, the maximum grafting percent and graft efficiency were 101% and 93%, respectively. Furthermore, a lower critical temperature of copolymers was measured in the range 29–31 °C by ultraviolet spectroscopy. The swelling behavior of graft membranes was carried out at various temperatures, and the results showed that the swelling behavior of membranes was dependent on the temperature. In vitro cell culture studies using L929 fibroblast cells confirmed cell compatibility with the PVA-g-PDEAAm copolymer and its membrane, making them an attractive candidate for drug delivery systems. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45969.
      PubDate: 2017-11-28T07:06:45.496624-05:
      DOI: 10.1002/app.45969
       
  • Effect of vinyl and phenyl group content on the physical and dynamic
           mechanical properties of HVBR and SSBR
    • Authors: Jing Hua; Kai Liu, Zhaobo Wang, Jieting Geng, Xin Wang
      Abstract: High-vinyl polybutadiene rubber (HVBR) and solution-polymerized styrene–butadiene rubber (SSBR) can meet the requirements of high-performance tires due to their excellent wet skid resistance and lower rolling resistance. In this paper, the effects of the vinyl and phenyl groups and their contents on the vulcanization behavior, mechanical strength, fatigue resistance, heat resistance, and wear resistance of HVBR and SSBR were investigated, and the dynamic viscoelasticities of HVBR and SSBR vulcanizates with or without carbon black were explored by dynamic mechanical analysis (DMA). The experimental results showed that the vinyl groups contributed more to the wear resistance and fatigue resistance of vulcanizates than the phenyl groups, but the phenyl groups contributed more to the mechanical strength of the vulcanizates than the vinyl groups. The DMA results showed that the vinyl and phenyl groups could significantly improve the road-gripping capability and wet skid resistance of HVBR and SSBR vulcanizates, but carbon black could slightly weaken the effect of vinyl and phenyl groups on the wet skid resistance of vulcanizates, and the effect of carbon black on vinyl groups was more significant. Despite the presence of carbon black, the phenyl groups contributed more heat buildup to the vulcanizates than the vinyl groups. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45975.
      PubDate: 2017-11-28T07:06:35.454546-05:
      DOI: 10.1002/app.45975
       
  • Development of biodegradable PLA/PBT nanoblends
    • Authors: Luiza Gouvêa Santos; Lidiane Cristina Costa, Luiz Antonio Pessan
      Abstract: Poly(lactic acid)/poly(butylene terephthalate) (PLA/PBT) blends with 3, 5, and 10 wt % of PBT were produced in a twin-screw extruder, with the addition of ethylene–glycidyl methacrylate copolymer as compatibilizer. An uncompatibilized PLA/PBT blend with 5 wt % of PBT was prepared for comparison studies. The epoxy reactive groups in the compatibilizer allowed modification of the interfacial tension in the blends and reduced the PBT dimensions. The crystallinity of the blends was studied, and its influence on mechanical properties was analyzed. Tensile tests showed an increase in strain at break from 3% for neat PLA to 49% for PLA with 3 wt % PBT, while the tensile modulus dropped from 3.59 GPa to 3.35 GPa for the same samples. Izod results showed a transition from a brittle behavior of PLA to a ductile one for compatibilized blends. These results indicate that the nanometer-size dispersed phase was effective in changing the deformation behavior of the matrix without a significant loss of modulus. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45951.
      PubDate: 2017-11-28T07:06:31.431961-05:
      DOI: 10.1002/app.45951
       
  • Effect of carbon nanotube on PA6/ECO composites: Morphology development,
           rheological, and thermal properties
    • Authors: Elnaz Esmizadeh; Abdollah Irani, Ghasem Naderi, Mir Hamid Reza Ghoreishy, Charles Dobious
      Abstract: Thermoplastic elastomer (TPE) nanocomposites based on polyamide-6 (PA6)/poly(epichlorohydrin-co-ethylene oxide) (ECO)/multiwall carbon nanotube (MWCNTs) were prepared by melt compounding process. Different weight ratios of ECO (20, 40, and 60 wt %) and two kinds of functionalized and non-functionalized MWCNTs were employed to fabricate the nanocomposites. The morphological, rheological, and mechanical properties of MWCNTs-filled PA6/ECO blends were studied. The scanning electron microscopy of PA6/ECO blends showed that the elastomer particles, ECO, are well-dispersed within the PA6 matrix. The significant improvement in the dispersibility of the carboxylated carbon nanotubes (COOH-MWCNTs) compared to that of non-functionalized MWCNTs (non-MWCNTs) was confirmed by transmission electron microscopy images. The tensile modulus of samples improved with the addition of both types of MWCNTs. However, the effect of COOH-MWCNTs was much more pronounced in improving mechanical properties of PA6/ECO TPE nanocomposites. Crystallization results demonstrated that the MWCNTs act as a nucleation agent of the crystallization process resulted in increased crystallization temperature (Tc) in nanocomposites. Rheological characterization in the linear viscoelastic region showed that complex viscosity and a non-terminal storage modulus significantly increased with incorporation of both types of MWCNTs particularly at low frequency region. The increase of rheological properties was more pronounced in the presence of carboxylic (COOH) functional groups, in the other words by addition of COOH-MWCNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45977.
      PubDate: 2017-11-28T07:06:27.459146-05:
      DOI: 10.1002/app.45977
       
  • Toughness of ABS/PBT blends: The relationship between composition,
           morphology, and fracture behavior
    • Authors: Lei Tang; Lulin Wang, Pingxu Chen, Jinfeng Fu, Peng Xiao, Nanbiao Ye, Mingqiu Zhang
      Abstract: A series of acrylonitrile–butadiene–styrene (ABS) copolymer/poly(butylene terephthalate) (PBT)/acrylonitrile-styrene-glycidyl methacrylate (ASG) blends with various compositions were prepared and characterized in this study. When the fraction of ABS exceeds a critical value there is a rapid increase in notched impact strength of ABS/PBT blends no matter whether the compatibilizer ASG is present. By combining morphology observation and notched impact results, we found that the ductile-brittle transition of the blends is closely related to the morphology inversion. The notched impact strength jumps from 15.9 to 33.4 kJ/m2 when phase inversion of ABS occurs at its fraction of 58 wt %. Accordingly, a possible toughening mechanism involved in the blends is proposed on the basis of a careful analysis of fracture energy, crack propagation behavior and fracture surface morphology. It is believed that the continuous ABS phase plays the critical role in toughening ABS/PBT blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46051.
      PubDate: 2017-11-27T08:57:32.746874-05:
      DOI: 10.1002/app.46051
       
  • Properties of natural rubber filled with untreated and treated spent
           coffee grounds
    • Authors: Chomsri Siriwong; Supparoek Boopasiri, Vanichaya Jantarapibun, Boonsong Kongsook, Sirichai Pattanawanidchai, Pongdhorn Sae-Oui
      Abstract: This work studied the properties of spent coffee ground (SCG) filled natural rubber (NR). The SCG was initially characterized by various techniques, prior to being added into rubber. Results revealed that SCG had relatively large particle size with very low specific surface area. It is mainly composed of organic compounds (such as protein, fatty acid, cellulose, hemicellulose, and lignin) with small quantity of inorganic substances (oxides of potassium, silicon, magnesium, calcium, and phosphorous). The incorporation of SCG in NR gave relatively low reinforcement and tended to retard vulcanization due to the presence of hydroxyl groups on the SCG surface. In addition to untreated SCG, reinforcement of SCG treated by liquid epoxidized natural rubber (LENR) and bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) was investigated. Improvement of rubber properties was observed when SCG surface was treated. Overall, TESPT-treated SCG gave the rubber with the highest mechanical properties, followed by LENR-treated SCG and untreated SCG, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46060.
      PubDate: 2017-11-27T08:57:15.544788-05:
      DOI: 10.1002/app.46060
       
  • Wetting measurements as a tool to predict the thermoplastic/thermoset
           rubber compatibility in two-component injection molding
    • Authors: Gert-Jan Bex; David Seveno, Jozefien De Keyzer, Frederik Desplentere, Albert Van Bael
      Abstract: Recently a novel two-component injection molding process has been developed combining thermoplastics with thermoset rubbers. Since the adhesion strength between the two materials strongly depends on the combination of a specific thermoplastic and a thermoset rubber, there is a need to predict their compatibility, defined as the formation of a strong interface. In this study, the wetting behavior of molten thermoplastics on rubber substrates is used to predict their compatibility since wetting is an essential step in the formation of a strong interface. Contact angle measurements at high temperatures showed that the wetting of polypropylene and polyethylene is the best in combination with ethylene propylene diene monomer rubber while nitrile rubber is best wetted by polycarbonate. The subsequent two-component injection molding tests confirm that it is possible to combine these materials. Material combinations with a poor wetting behavior on the other hand are not suitable for two-component injection molding. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46046.
      PubDate: 2017-11-27T08:57:07.929917-05:
      DOI: 10.1002/app.46046
       
  • Photografted polymeric networks based on N-isopropylacrylamide: Depth
           profiling by infrared spectroscopy
    • Authors: Mihaela Avadanei
      Abstract: The study presents the application of infrared spectroscopy in attenuated reflection geometry with variable angle of incidence (VA-ATR-FTIR) in analysis of the in-depth distribution of several chemical species in photografted layers. Two types of networks based on N-isopropylacrylamide (NIPA) and one interpenetrated network of NIPA and N,N-dimethylacrylamide (DMA) were produced by UV-induced graft polymerization on polypropylene surfaces. The NIPA-g-PP samples were obtained in two different UV irradiation conditions: under broad band irradiation and using soft UV light (λ > 300 nm). NIPA-co-DMA-g-PP has been obtained using λ > 300 nm. VA-ATR-FTIR spectroscopy revealed the distribution of NIPA and DMA units across the thickness of the probed layer, according to the network type and photografting conditions. The spectral analysis of NIPA-g-PP reveals the influence of irradiation conditions, particularly the UV-B radiation, on the coupling of monomers. For the NIPA-co-DMA-g-PP sample, a slight agglomeration of DMA units near the surface has been observed, which is maybe related to the more reactive character of DMA. According to the nonhomogenous distribution of the NIPA and DMA units inside the grafted layer, the surface contribution can be separated from the bulk one. The depth profile of several chemical species has been finally constructed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46048.
      PubDate: 2017-11-27T08:57:00.337262-05:
      DOI: 10.1002/app.46048
       
  • Formation of co-continuous PLLA/PC blends with significantly improved
           physical properties by reactive comb polymers
    • Authors: Dong Wenyong; Wang Xu, Li Yongjin
      Abstract: A kind of reactive comb (RC) polymer, which is constituted by poly(methyl methacrylate) backbone and side chains and a few epoxide groups that distribute randomly along the backbone, has been applied as compatibilizers for the thermodynamically immiscible poly(l-lactide) (PLLA)/polycarbonate (PC) blend (50/50, wt/wt). Phase morphology and physical properties of the compatibilized PLLA/PC blends are characterized by scanning electron microscopy, transmission electron microscopy, and tensile tests. It has been found that the morphologies of the PLLA/PC blends are significantly ameliorated with the addition of RC polymers. A type of PLLA/PC blend with stable co-continuous morphology has been achieved by the incorporation of more than 3 wt % of RC polymers. The mechanical tests showed that the co-continuous PLLA/PC blends have an excellent stiffness-toughness balance with high modulus and significantly improved ductility. Especially, the elongation at break of the PLLA/PC blend compatibilized by 10 wt % of RC polymers is 10 times higher than that of neat PLLA, in which the blend exhibits a cocontinuous lamellar microstructure. Furthermore, the PLLA/PC blends with cocontinuous morphology exhibit dramatically improved thermal stability as compared to neat PLLA when the temperature is over the Tg of the PLLA phase. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46047.
      PubDate: 2017-11-27T08:56:51.717652-05:
      DOI: 10.1002/app.46047
       
  • Starch-graphene oxide bionanocomposites prepared through melt mixing
    • Authors: Carlos A. Ávila-Orta; Florentino Soriano Corral, Heidi A. Fonseca-Florido, Flor I. Estrada Aguilar, Silvia G. Solís Rosales, José M. Mata Padilla, Pablo González Morones, Salvador Fernández Tavizón, Ernesto Hernández-Hernández
      Abstract: Bionanocomposites (BNCs) of waxy corn starch, glycerol, and graphene oxide (GO) or graphite oxide (GrO) were prepared by melt mixing. First, the GrO was pre-exfoliated in a water solution using ultrasound at 1 wt %. Small-angle X-ray scattering was used to determinate the interlaminar separation of GrO and transmission electron microscopy, Fourier infrared spectroscopy, and thermogravimetric analysis were used to characterized the GrO. Next, BNCs were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and mechanical property measurements. A complete exfoliation of GrO was obtained in the waxy corn matrix. Amorphous X-ray patterns of the BNCs were observed, indicating that the exfoliated GO avoid the retrogradation of starch. According to scanning electron microscopy results, the BNCs showed an irregular texture and a good dispersion of GO, while thermoplastic starch showed a smooth morphology with a fragile structure. The BNCs exhibited higher thermal stability than thermoplastic starch. The tensile strength and the Young's modulus increased by 140% and 230% at a GO loading levels of 0.5% due to good interfacial interactions of GO and the waxy corn starch matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46037.
      PubDate: 2017-11-27T08:56:41.887349-05:
      DOI: 10.1002/app.46037
       
  • Benign route for the modification and characterization of poly(lactic
           acid) (PLA) scaffolds for medicinal application
    • Authors: Shebi Alippilakkotte; Lisa Sreejith
      Abstract: Scaffolds fabricated from polymers have imprinted its wide applicability in the field of tissue engineering. The surface of electrospun poly(lactic acid) (PLA) nanofibers was modified to improve their compatibility with living medium. PLA film were treated with alkali solution to introduce carboxyl groups on the surface followed by covalent grafting of gelatin using Xtal Fluoro-E as coupling agent. The gelatin g-PLA polymer synthesized via ‘graft-onto’ method exhibit fascinating properties as studied by contact angle measurement, fourier transformed infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, water vapor transmission rate(WVTR), swelling studies and differential scanning calorimetry. The fabricated gelatin g-PLA scaffolds were further characterized to conduct the study on hydrolytic degradation, and extent of biodegradation at ambient temperature. It was observed from the in-vitro analysis that the gelatin g-PLA nanofiber (with hemolytic percentage, 0.56 ± 0.13%) was cytocompatible with fibroblast cell and does not impair cell growth. The WVTR obtained for the electrospun mat around 2900 ± 100 g/m2. 24 h signifies the optimal moist environment required for tissue engineering especially wound healing. Notably, many of these strategies resulted in porous hydrophilic scaffolds with human cell growth and proliferation for medical applications of various types. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46056.
      PubDate: 2017-11-27T08:56:26.889051-05:
      DOI: 10.1002/app.46056
       
  • Cover Image, Volume 135, Issue 10
    • Abstract: The SEM image from Juan Francisco Rodriguez and colleagues displays the morphology of thermoregulating styrene-divinylbenzene microcapsules containing unsaturated fatty acids as Phase Change Materials (PCMs). The microcapsules are nearly perfectly spherical with a smooth surface. The radical-polymerized fatty acids are able to react with vinyl monomers in the polymeric shell structure. (
      DOI : 10.1002/app.45970)
      PubDate: 2017-11-27T05:36:56.533427-05:
       
  • Editorial Board, Aims & Scope, Table of Contents
    • PubDate: 2017-11-27T05:36:55.183068-05:
      DOI: 10.1002/app.45592
       
  • Mechanical properties of 3D printed polycaprolactone honeycomb structure
    • Authors: Pengfei Zhang; Donald Joseph Arceneaux, Ahmed Khattab
      Abstract: Polycaprolactone is well known as a healing agent material in crack self-healing applications but not as a structural material. In this study, the focus is on the durability and energy absorption of honeycomb structure made from polycaprolactone through three-dimensional (3D) printing. The mechanical behavior of honeycomb structures was investigated through in-plane quasi-static compression tests at temperatures of 5 °C, room temperature (22 °C), and 40 °C. Energy absorption efficiency and energy absorption capability at different temperatures and in different loading directions was investigated according to the selected stepping upward stress. The “shape recovery” ratio after compression deformation was calculated. The results reveal that the polymeric honeycomb structure has exceptional repeatability under compressive loads. Specimens with relative density 0.20 showed high energy absorption capability, up to 0.988 J cm−3. After the removal of compression loads, specimens recovered up to 80% after the first deformation and up to 70% after the fifth deformation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46018.
      PubDate: 2017-11-27T00:37:33.651469-05:
      DOI: 10.1002/app.46018
       
  • Effect of two different plasticizers on the properties of
           poly(3-hydroxybutyrate) binary and ternary blends
    • Authors: Irene Teresita Seoane; Liliana Beatriz Manfredi, Viviana Paola Cyras
      Abstract: Plasticized poly(3-hydroxybutyrate) (PHB) films were obtained by solvent casting. The effects of two different additives on several properties of PHB have been examined, utilizing tributyrin and poly[di(ethyleneglycol) adipate] (A). Based on changes in the glass transition temperature (Tg) and cold crystallization temperature of host PHB, the two components are miscible with PHB and they can act as plasticizers. Binary and ternary blends were obtained by adding both plasticizers separately or together, respectively. The effect of plasticizer addition on the optical transparency, water vapor permeability, and tensile properties of the films was studied. It was found that the blends remain transparent and water vapor permeability was maintained constant until a 20 wt % of plasticizer content. Plasticizing effect was corroborated and it depended on the plasticizer percentage. Binary blends had an increased plasticity, in concordance with Tg diminution of PHB. Although ternary blends presented Tg diminution, mechanical properties were not improved probaby due to strong interactions between plasticizers. Finally, binary and ternary blends presented enhanced properties, causing an increment on processability. A correct knowledge between the formulation of the film and the role played by each component could allow getting custom films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46016.
      PubDate: 2017-11-27T00:36:49.232509-05:
      DOI: 10.1002/app.46016
       
  • Incorporation of carbon nanofibers into a Matrimid polymer matrix: Effects
           on the gas permeability and selectivity properties
    • Authors: Manisha Dohade
      Abstract: Composite membranes containing carbon nanofibers (CNFs) and Matrimid were prepared by a solution-casting method. Prepared Matrimid–CNF composite membranes were characterized with X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and mechanical testing techniques. The mechanical properties of the composite membranes increased over that of the pristine polymeric membranes. To develop a broad fundamental understanding of the connection between the composite architecture and gas-transport properties, both the gas-permeability and gas-separation characteristics were evaluated. The gas-transport properties of the Matrimid–CNF composite membrane was measured with a single gas-permeation setup (He, H2, N2, CH4 and CO2) at ambient temperature with the variable-volume method. The incorporation of CNFs (0.5–10 wt %) into the Matrimid matrix resulted in approximately a 22% reduction in the gas permeation of various gases, (H2, He, CO2, N2, and CH4). Moreover, an improvement of 1.5 times in the gas selectivity was observed for CO2/CH4, H2/CH4, He/CH4, and H2/N2 compared to pristine polymeric membrane. Hence, such polymer–CNF composite membranes could be suitable for gas-separation applications with high purity requirements. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46019.
      PubDate: 2017-11-27T00:36:35.644226-05:
      DOI: 10.1002/app.46019
       
  • Valorization of waste thermoset material as a filler in thermoplastic:
           Mechanical properties of phenolic molding compound waste-filled PP
           composites
    • Authors: Fabien Bernardeau; Didier Perrin, Anne-Sophie Caro, Jean-Charles Benezet, Patrick Ienny
      Abstract: As most thermoset material, phenolic molding compound (PMC) wastes are an environmental problem. Very few recycling solutions have been proposed so far for this type of material. A mechanical recycling method to valorize these materials is proposed in this work. It relies on the use of phenolic waste as filler in thermoplastic. Such phenolic filler can increase mechanical properties (tensile, flexural) of the matrix, and be used in substitution of traditional particulate fillers such as calcium carbonate or talc. In this study, several morphological parameters influencing the final mechanical properties of a PMC-filled polypropylene (PP) micro-composite are studied, such as filler loading rate, particles size distribution of the filler, and interfacial adhesion between the filler and the matrix. Some structural parameters are also studied and linked with mechanical properties, such as dispersion of the filler and crystallinity of the matrix. Finally, the properties of PMC-filled PP are compared with CaCO3- and talc-filled PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45849.
      PubDate: 2017-11-27T00:36:26.657653-05:
      DOI: 10.1002/app.45849
       
  • RAFT-mediated emulsion polymerization of chloroprene and impact of
           chain-end structure on chloroprene rubbers
    • Authors: Yuhei Ishigaki; Hideharu Mori
      Abstract: The reversible addition-fragmentation chain transfer (RAFT) polymerization of chloroprene (CP) in an emulsion system using a dithiocarbamate-type RAFT agent was studied. The controlled RAFT-mediated emulsion polymerization was achieved by the appropriate combination of a RAFT agent and nonionic surfactant (polyoxyethylene phenyl ether) using a water-soluble initiator (VA-044) at 35 °C. An almost linear first-order kinetic plot was observed until relatively high conversion (>80%) with molecular weights between 22,300 and 33,100 and relatively narrow molecular weight distributions (Mw/Mn ≦ 1.5) were achieved. The amount of the emulsifier used and the pH of the system were found to affect the controlled character, polymerization rate, and induction period, which are related to the size of the emulsion particles. Large-scale RAFT-mediated emulsion polymerization was also employed to afford industrially applicable poly(CP) (Mw > 25 × 104, resulting product > 2300 g). The vulcanized CP rubber obtained from the RAFT-synthesized poly(CP) exhibited better physical properties, particularly tensile modulus and compression set, which may be due to the presence of the reactive end groups and the absence of low-molecular-weight products. We also evaluated the impact of the chain-end structure on the mechanical and physical properties of these industrially important CP rubbers with carbon black. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46008.
      PubDate: 2017-11-27T00:36:16.296732-05:
      DOI: 10.1002/app.46008
       
  • Traditional and innovative protective coatings for outdoor bronze:
           Application and performance comparison
    • Authors: Barbara Salvadori; Andrea Cagnini, Monica Galeotti, Simone Porcinai, Sara Goidanich, Antonello Vicenzo, Claudio Celi, Piero Frediani, Luca Rosi, Marco Frediani, Giulia Giuntoli, Laura Brambilla, Ruben Beltrami, Stefano Trasatti
      Abstract: A comparative evaluation of traditional and innovative coatings for outdoor bronze surfaces was carried out, including blending or pre-treatment with non-toxic corrosion inhibitors on bare and patinated bronze surfaces to simulate both as cast and aged surfaces. Coatings recently applied in bronze conservation practice, commercially available coatings and an innovative end-capped poly(lactic acid) with a benzotriazole (BTA) moiety have been tested, as well as a triple-layer system (wax/acrylic polymer/wax). BTA, single-layer Soter wax, and double layer Incral44/Soter wax were used as a reference. The products were evaluated in terms of aesthetic features, molecular structure, and corrosion protection by means of colorimetric, spectroscopic, and electrochemical tests. All inhibitors showed similar or significantly better results compared to BTA. In particular, sodium oleate and tolyltriazole could be considered as promising lower-toxicity alternatives to BTA, while the triple-layer coating applied without pre-filming inhibitors proved to give a very high protection against corrosion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46011.
      PubDate: 2017-11-27T00:36:12.155725-05:
      DOI: 10.1002/app.46011
       
  • Electrochromic properties of some bis-chalcone derivatives-based
           nanofibers
    • Authors: Neslihan Nohut Maşlakcı; Abdullah Biçer, Günseli Turgut Cin, Ayşegül Uygun Öksüz
      Abstract: Two bis-chalcone derivatives, (2E,6E)-2,6-bis[(thiophen-2-yl)methylene]cyclohexanone (C1) and (2E,6E)-2,6-bis[(furan-2-yl)methylene]cyclohexanone (C2)-based electrochromic (EC) nanofibers were produced in the presence of poly(methyl methacrylate) (PMMA) as supporting polymer using the electrospinning technique. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy were used to examine morphology and chemical compositions of nanofibers before and after stability test. SEM images of the obtained smooth and bead-free nanofibers before the stability test showed that both bis-chalcone derivatives were homogeneously dispersed on the surface of the electrospun nanofibers. Nanofibers of bis-chalcone derivatives were characterized with Fourier-transform infrared spectroscopy. The electrochemical and EC properties of these bis-chalcone derivatives were investigated. The C1-PMMA nanofiber-based electrochromic device (ECD) showed higher ΔTmax (41.47%) than that of the C2-PMMA nanofiber-based ECD (4.67%) during coloration/bleaching at 715 nm. The switching times for coloration and bleaching of C1-PMMA nanofiber-based ECD were found to be 4.42 and 1.12 s, respectively, and the coloration efficiency was 136.18 cm2/C. Repeated cyclic voltammograms and 1000 cycles of chronoamperometric measurements of the bis-chalcone derivatives indicated that ECDs have long-term redox stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46010.
      PubDate: 2017-11-27T00:36:04.02359-05:0
      DOI: 10.1002/app.46010
       
  • Effects of relaxation time and zero shear viscosity on structural
           evolution of linear low-density polyethylene in shear flow
    • Authors: Kun Li; Go Matsuba
      Abstract: The purpose of this work is to investigate the precursor formation and crystallization of four different types of linear low-density polyethylene in shear flow. The aggregation of string-like structure (precursor) in micrometer scale was observed by polarized optical microscopy. Although the existence of precursors accelerates crystallization, we find that it is unnecessary for the polymer fluid to possess crystalline structures at relatively high temperatures by wide-angle X-ray diffraction. The rotational rheometer result suggests that relaxation time is consistent with processes of the precursor formation observed at 120 °C, while zero shear viscosity affects the boundaries of their corresponding processing windows. According to these results, we propose a mechanism that the precursor formation consists of entanglement and relaxation stages. Entanglements preserve the ordered state of polymer chains, while they return to the initially disordered state during the relaxation stage. Under shearing, the polymer chain is oriented along the flow direction, and the degree of chain motion remains limited because the oriented parts are confined by the entanglements (characterized by zero shear viscosity η0) acting as slip-links. However, some chain motions and relaxation (characterized by terminal relaxation time τ) can still take place during this stage. Afterwards, the polymer chain becomes disordered and some entanglements disappear. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46053.
      PubDate: 2017-11-27T00:35:54.789063-05:
      DOI: 10.1002/app.46053
       
  • Novel imidazole-grafted hybrid anion exchange membranes based on
           poly(2,6-dimethyl-1,4-phenylene oxide) for fuel cell applications
    • Authors: Jiqin Chen; Chunhui Shen, Shanjun Gao, Yuan Yuan, Xuechao Ren
      Abstract: Novel organic–inorganic hybrid membranes, based on poly(2,6-dimethyl-1,4-phenylene oxide), have been prepared through 1,2-dimethylimidazole functional groups and double crosslinking agents including 3-glycidyloxypropyltrimethoxysilane and tetraethyl orthosilicate by sol–gel process for the purpose of improving the conductivity and alkaline resistance. The structure of membranes was characterized using Fourier-transform infrared spectra, 1H NMR, and X-ray diffraction. The physico-chemical properties of all membranes were shown in ion exchange capacity, water uptake, stability, and conductivity. Membranes with OH– conductivity up to 0.022 at 25 °C and 0.036 S cm−1 at 80 °C. Promisingly, the chemical stability of the resulting membranes remains unchanged after storage in 2 mol dm−3 KOH at 25 °C over at least 10 days. The tensile strength can be higher than 30 MPa, and the elongation at break (Eb) is in the range 6.68–10.84%. Hence, this hybrid membrane can be potentially applied in alkaline fuel cells. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46034.
      PubDate: 2017-11-27T00:35:48.714745-05:
      DOI: 10.1002/app.46034
       
  • Chitosan functionalization with a series of sulfur-containing α-amino
           acids for the development of drug-binding abilities
    • Authors: Reena Tondwal; Man Singh
      Abstract: Chitosan (Chi; 0.5 g) in 69.66 mM aqueous acetic acid was mixed with 312.4 mM methionine (methi) at 0.01 mL/s to disperse and cause optimum collisions for supporting condensation reactions through NH2 of Chi and COOH groups of methi. The functionalized chitosan (f-Chi) product with methi developed an amide bond, which was represented as methi-functionalized chitosan [Chi–NHC(O)–methi]. Both the 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and Dean–Stark methods were followed for Chi functionalization. Sulfonation with chlorosulfonic acid in a dimethylformamide medium was conducted at 90 °C and 750 rpm with an approximately 72% yield. The Chi–NHC(O)–methi was characterized by 1H-NMR spectroscopy and Fourier transform infrared stretching frequencies. The onset temperature of 280 °C recorded by thermogravimetric analysis/differential scanning calorimetry analysis, confirmed the high stability of the covalent bonds in Chi–NHC(O)–methi. The synthesis was repeated with other series members of sulfur (S) atoms containing α-amino acids: homocysteine, ethionine, and propionine. The shielding of terminal CH3 was enhanced on elongation of the terminal alkyl chain in the case of propionine. The peak for the NH2 of Chi at a δ value of 4.73 ppm shifted to 5.36 ppm in Chi–NHC(O)–methi because of the involvement of NH2 in NHC(O). Theoretically, the value of NH2 of Chi was 5.11 ppm, with a difference of 0.38 ppm as compared to the experimentally determined value of 4.73 ppm. Additionally, a new peak at a δ value of 3.26 ppm also confirmed Chi functionalization. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46000.
      PubDate: 2017-11-27T00:35:43.665631-05:
      DOI: 10.1002/app.46000
       
  • Evolution of double crystal melting peak in polypropylene foam assisted by
           β-nucleating agent and supercritical CO2
    • Authors: Kesong Yu; Hanchuan Jiang, Hongfu Zhou, Jianguo Mi, Yadong He, Xiangdong Wang
      Abstract: Polypropylene (PP) foams with double crystal melting peak structure were prepared using supercritical CO2 as blowing agent. Such structure was induced by the β-nucleating agent (NA) and dissolved CO2 in a lab-scale autoclave system. From the dynamic rheological behaviors, one can see that long chain branching polypropylene (LCBPP) possess better melt elasticity than linear polypropylene (LPP). In order to improve the foamability, LPP was blended with LCBPP. The results of differential scanning calorimeter and wide-angle X-ray diffraction indicated that NA was helpful for the introduction of β-crystal in LPP, but not for LCBPP and PP blends. Therefore, the foamability and the content of β-crystal of various PP foams can be effectively controlled by adjusting the ratio of LPP and LCBPP. Meanwhile, both the cooling rate and the content of NA affected the formation of β-crystal in various PP samples. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46007.
      PubDate: 2017-11-27T00:35:39.550646-05:
      DOI: 10.1002/app.46007
       
  • Highly toughened polylactide by renewable Eucommia ulmoides gum
    • Authors: Hailan Kang; Lei Yao, Yushi Li, Xiaoran Hu, Feng Yang, Qinghong Fang, Liqun Zhang
      Abstract: Polylactide (PLA) derived from natural sources has attracted increasing interest and has provided a promising alternative to traditional plastics derived from petroleum sources. With no loss of environmental friendly features, PLA was highly toughened by Eucommia ulmoides gum (EUG) derived from Eucommia ulmoides oliv. The dynamic mechanical analysis, scanning electron microscopy (SEM), and differential scanning calorimetry results show that the PLA–EUG blends were immiscible systems. SEM micrographs revealed that EUG particles were well dispersed in the PLA matrix with number-average particle diameters of 2–4 μm. The mechanical properties indicated that the tensile strength decreased with increasing EUG contents, but the elongation at break and the impact strength were enhanced. The notched impact strength of the blends improved by 5.9-fold compared to that of neat PLA. The PLA–EUG blends exhibited distinct shear-thinning behavior; this indicated good processability, and the storage modulus and loss modulus of the PLA–EUG blends increased with EUG content. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46017.
      PubDate: 2017-11-27T00:35:32.435652-05:
      DOI: 10.1002/app.46017
       
  • Kinetics of short-duration ethylene–propylene copolymerization with
           MgCl2-supported Ziegler–Natta catalyst: Differentiation of active
           centers on the external and internal surfaces of the catalyst particles
    • Authors: Akbar Khan; Yintian Guo, Zhen Zhang, Amjad Ali, Zhisheng Fu, Zhiqiang Fan
      Abstract: Ethylene–propylene copolymerization with a TiCl4/MgCl2 type ZN catalyst was conducted for different durations from 30 to 600 s, and changes of polymerization rate, concentration of active centers ([C*]) and copolymer chain structure with time were traced. The copolymerization rate decayed with time, but [C*]/[Ti] increased in the same period. This was attributed to release of more active sites through disintegration of catalyst particles by the growing polymer phase. Ethylene content of the copolymer quickly decreased in the period of 30–90 s, meaning that the active centers activated in the reaction process have stronger ability of incorporating propylene than those activated at the very beginning. The copolymer samples were fractionated into two parts, namely n-heptane soluble fraction (random copolymer) and insoluble fraction (segmented copolymer with high ethylene content). With continuation of the copolymerization, active centers producing the random copolymer chains increased much faster than active centers producing the segmented copolymer chains, and became the dominant centers after 120 s. Consequently, proportion of the soluble fraction sharply increased with time. All these results indicate that the active centers located on the external surface of catalyst particles are highly different from those buried inside the particles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46030.
      PubDate: 2017-11-23T00:32:16.580334-05:
      DOI: 10.1002/app.46030
       
  • Synthesis and characterization of bio-based PA/EP interpenetrating network
           polymer as coating material for controlled release fertilizers
    • Authors: Cong Jia; Xiao Zhang, Yufeng Li, Yanghui Jiang, Min Zhang, Panfang Lu, Hongkun Chen
      Abstract: A novel controlled release fertilizer was developed using interpenetrating polymer network (IPN) as the coating material. The IPN was successfully sprayed on the surface of the urea particles to form IPN-coated fertilizers (IPNCU) for controlled nitrogen release. The IPN was synthesized by bio-based polyamide (PA) from d-glucaric acid and epoxy (EP) through network interpenetrating. The chemical structure and microscopic morphology characteristics of IPN were examined by Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance, and scanning electron microscopy. The property of IPN with the different PA/EP mass ratios were investigated and compared with that of EP-coated fertilizers (EPCU). The nutrient release behaviors of IPNCU in water and soil were detected. The results showed that the IPNCU with 5% PA content increased the nitrogen release longevity by 41 days, raised the water contact angle of surface by 23.9°, and then significantly slowed the nitrogen release rate of the IPNCU. The nutrient release mechanism of IPNCU was discussed in detail. This work indicated that the environment-friendly IPN with superior controlled release properties could be especially useful in horticultural and agricultural applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46052.
      PubDate: 2017-11-23T00:32:05.806318-05:
      DOI: 10.1002/app.46052
       
  • COOHMWCNTs-induced BiFeO3-poly(vinylidene fluoride) (PVDF) composites with
           enhanced dielectric and ferroelectric properties
    • Authors: Srikanta Moharana; Ram Naresh Mahaling
      Abstract: In this work, flexible three phase composite films were prepared with surface functionalized multi-walled carbon nanotubes (f-MWCNTs) and bismuth ferrite (BiFeO3;BFO) particles embedded into the poly(vinylidene fluoride) (PVDF) matrix via solution casting technique. The properties and the microstructure of prepared composites were investigated using an impedance analyzer and field emission scanning electron microscope. The micro-structural study showed that the f-MWCNTs and BFO particles were dispersed homogeneously within the PVDF matrix, nicely seated on the floor of the f-MWCNTs separately. The dielectric measurement result shows that the resultant composites with excellent dielectric constant (≈96) and relatively lower dielectric loss (
      PubDate: 2017-11-23T00:31:45.516449-05:
      DOI: 10.1002/app.46002
       
  • Development of sericin/alginate particles by ionic gelation technique for
           the controlled release of diclofenac sodium
    • Authors: Jacyara Moreira Martins Vidart; Thiago Lopes da Silva, Paulo César Pires Rosa, Melissa Gurgel Adeodato Vieira, Meuris Gurgel Carlos da Silva
      Abstract: Sericin and alginate particles, prepared by ionic gelation technique, demonstrated to be a promising matrix to controlled release of diclofenac sodium. Ten particle compositions of sericin, alginate, and diclofenac were evaluated. The drug incorporation was confirmed by scanning electron microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction analysis. In vitro dissolution profile was performed to obtain the drug release profile in gastric and enteric medium. The drug release profile indicated that sericin delays the release and alginate contributes to the gastro-resistance of formulations. The blend with composition of 2.5% of sericin, 2.8% of alginate with 2.0% w/v of diclofenac demonstrated to be feasible for drug delivery due the entrapment efficiency of 81.06% and release delay of 360 min, the highest time of all investigated compositions. The mathematical modeling showed that the drug release mechanism is associated to the process of swelling, matrix erosion, and a combination of diffusion and chain relaxation mechanisms. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45919.
      PubDate: 2017-11-23T00:31:40.099499-05:
      DOI: 10.1002/app.45919
       
  • Octadecyl-silica—PVDF membrane of superior MD desalination
           performance
    • Authors: Rupal J. Mistry; Mayank Saxena, Paramita Ray, Puyam S. Singh
      Abstract: Despite its widespread industrial and residential uses for production of potable water, the reverse osmosis (RO) desalination process has some drawbacks by discharging harmful concentrated saline water as reject stream. A hydrophobic porous membrane can treat such environmentally unfriendly RO reject stream via Membrane Distillation (MD) process. Here, we describe preparation of superior polyvinylidenefluoride (PVDF) membrane modified with superhydrophobic silica nanoparticles for desalination application. Superhydrophobicity (contact angle of 151°) of silica nanoparticles of 7 nm sizes was achieved by reaction of the silica particles with octadecyltrichlorosilane in toluene to form SiOSi links with C18 alkyl chain. A homogeneous polymer dope mixture containing a desired amount of modified silica colloids suspended in toluene was used for the membrane preparation. The PVDF membrane with optimal silica content exhibited excellent flux with>99% salt rejection efficiency when used for MD at room temperature from the saline water feed of 3.5 wt % NaCl. The prepared hydrophobic PVDF membrane has the potential for MD application in treating the RO reject stream and other aqueous industrial effluents. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46043.
      PubDate: 2017-11-23T00:31:33.762573-05:
      DOI: 10.1002/app.46043
       
  • Quaternized poly(2.6 dimethyl-1.4 phenylene oxide)/polysulfone blend
           composite membrane doped with ZnO-nanoparticles for alkaline fuel cells
    • Authors: Phumlani Fortune Msomi; Patrick Nonjola, Patrick Gathura Ndungu, James Ramonjta
      Abstract: A series of quaternized poly(2.6 dimethyl-1.4 phenylene oxide)/polysulfone (QPPO/PSF) blend anion exchange membrane (AEM) were successfully fabricated and characterized for alkaline fuel cell application. Zinc oxide (ZnO) nanoparticles were introduced in the polymer matrix to enhance the intrinsic properties of the AEM. To confirm successful fabrication, Fourier-transform infrared spectroscopy and nuclear magnetic resonance (1H-NMR) were used. The membrane properties were enhanced by the addition of ZnO nanoparticles. The addition of ZnO nanoparticles resulted to a higher ion exchange capacity (IEC) of 3.72 mmol g−1, increase of ion conductivity (IC) up to 52.34 mS cm−1 at 80 °C, enhancement of water uptake, and reduced methanol permeability. The QPPO/PSF/2% ZnO composite retained over 80% of its initial IC at room temperature and also retained over 50% of its initial IC at 80 °C when evaluated for alkaline stability. The maximum power output reached for the membrane electrode assembly constructed with QPPO/PSF/2%ZnO was 69 mW cm−2 at room temperature, which is about three times more than the parent QPPO membrane. The above results indicate that QPPO/PSF/ZnO is a good candidate as an AEM for fuel cell application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45959.
      PubDate: 2017-11-16T05:11:06.656679-05:
      DOI: 10.1002/app.45959
       
  • Infrared laser-ignited horizontal frontal polymerization of versatile
           unsaturated polyester resins
    • Authors: Nigus Mesele Tsegay; Xiang-Yun Du, Kangzhe Ma, Qing Li, Cai-Feng Wang, Su Chen
      Abstract: Infrared laser-ignited horizontal frontal polymerization is applied for the synthesis of unsaturated polyester resin (UPER) by copolymerizing unsaturated polyester with styrene (St), methyl methacrylate (MMA), and 2-dimethylamino ethyl methacrylate (DMAEMA) monomers. Dependence of frontal velocity and temperature on the initiator and monomer concentration is discussed for St-based UPER. These resins have also been characterized by Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. The results reveal St-based resins have superior crosslinked networks. Besides, the thermo-pH responsiveness behaviors of DMAEMA-based resins are demonstrated by swelling measurements under the conditions of different temperatures and pH values. Moreover, by introducing CdSe@ZnS quantum dots and CsPbBr3 perovskites into St- and MMA-based resins, respectively, we realize the in situ generation of CdSe@ZnS-UPER and CsPbBr3-UPER composites with good fluorescence properties and fluorescent stability, which have potential application in optoelectronic devices such as light-emitting diode and perovskite solar cells. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45935.
      PubDate: 2017-11-16T05:10:53.618255-05:
      DOI: 10.1002/app.45935
       
  • Graphene oxide/poly(ethylene glycol)/chitosan gel with slow-release
           lubrication applied on textured surface
    • Authors: Shanshan Ren; Hailin Lu, Junde Guo, Yue Li, Xing Li, Jianhui Li, Guangneng Dong
      Abstract: Graphene oxide/poly(ethylene glycol) (GO/PEG) composites that have biocompatibility and biodegradability properties have been prepared to improve the lubrication of artificial joints, but they would be rapidly degraded and absorbed by the human body if injected. To prolong the lubrication effect, GO/PEG lubricants were mixed into a chitosan (CS) sol, and then the GO/PEG/CS sol was added to the dimpled texture of a Co-Cr-Mo alloy and transformed into a gel to slowly release GO/PEG lubricants. The results of friction experiments showed that the average friction coefficient of the slow-release solution is below 0.025, especially when under pressure, and the gel in the texture also has a good lubrication effect. Meanwhile, the FTIR and UV–vis of the slow-release solution indicated that it is likely to contain GO, PEG, and CS, which are associated with each other via hydrogen bonds and may form a particular structure, leading to good slow-release lubrication. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45818.
      PubDate: 2017-11-16T05:10:39.126104-05:
      DOI: 10.1002/app.45818
       
  • Impact of lignin extraction methods on microstructure and mechanical
           properties of lignin-based carbon fibers
    • Authors: Xiaojuan Shi; Xing Wang, Biao Tang, Zhong Dai, Kefu Chen, Jinghui Zhou
      Abstract: In order to optimize the use of residues of enzymatic hydrolysis of corn stalk (REHCS) and explore the low-cost and sustainable raw material substitute for carbon fibers, three types of lignin samples were extracted from REHCS by various extraction methods, and then they were converted into carbon fibers (CFs) by electrospinning, thermostabilization, and carbonization under the same process conditions. The microstructure and mechanical properties of the three types of carbonized fibers were different. The CFs from the ethanol organosolv lignin were actually smooth and brittle carbon films. The CFs from the formic acid/acetic acid organosolv lignin had microscopic pores, causing poor mechanical properties. Comparatively, the CFs from the alkaline lignin demonstrated preferable microstructure and mechanical properties. The reasons for the differences were analyzed by characterizing the lignin samples, precursor fibers, and resultant CFs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45580.
      PubDate: 2017-11-16T05:10:32.11385-05:0
      DOI: 10.1002/app.45580
       
  • Gas-permeation performance of metal organic framework/polyimide
           mixed-matrix membranes and additional explanation from the particle size
           angle
    • Authors: Cuijia Duan; Xingming Jie, Haitao Zhu, Dandan Liu, Weiming Peng, Yiming Cao
      Abstract: With MOFs of Cu3(BTC)2 and ZIF-8 as the dispersed phases and four polyimides with CO2 permeabilities ranging from 1.36 to 564 barrer as the continuous phase, the influence of metal organic frameworks on the gas-separation properties of mixed-matrix membranes (MMMs) was investigated. The results show that the gas permeabilities of all of the prepared MMMs greatly increased and even largely exceeded the predicted value of the Bruggeman model; for example, with the same Cu3(BTC)2 loading of 21.3 vol %, the O2 permeability increase rate of our prepared Cu3(BTC)2/Matrimide 5218-20 MMMs was 2.26 times, whereas that predicted by the Bruggeman model was only 1.05 times. In addition, when the gas permeability of the polymeric phase was far lower than the dispersed phase of ZIF-8 or Cu3(BTC)2 compared with ZIF-8, which had a particle size (R) around 150 nm, Cu3(BTC)2 of 5–15 µm showed a little better enhancing effect on the gas-permeation performance of the MMMs. In addition to the properties of the dispersed and continuous phases, we speculated that the ratio between R of the dispersed phase to the membrane thickness (L) played an important role for MMMs; the larger R/L was, the greater the gas permeability of the MMMs was. This speculation was initially evidenced by the ZIF-8/ODPA/TMPDA-20 MMMs with different Ls. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45728.
      PubDate: 2017-11-14T05:30:39.61198-05:0
      DOI: 10.1002/app.45728
       
  • A comprehensive investigation of dye–chitosan blended films for
           green chemistry applications
    • Authors: Vito Rizzi; Alessandra Longo, Tiziana Placido, Paola Fini, Jennifer Gubitosa, Teresa Sibillano, Cinzia Giannini, Paola Semeraro, Esther Franco, Marcela Ferrandiz, Pinalysa Cosma
      Abstract: In this paper, the ability of chitosan film to remove dyestuff from wastewater was evaluated for environmental applications, using three commercial direct azo dyes. Two chitosan films were adopted: the standard one prepared following a well-known procedure to form it, and a novel one, with a weakly acidic character. Moreover, to improve the adsorption process, the hydrophobic character of the films was investigated. The pH of the dye solutions was also changed, showing an excellent ability in dye removal at pH 12. The films were characterized by means of spectroscopic and morphologic methods to better understand the nature of interactions between dyes and chitosan chains. Swelling ratio measurements were also performed. All analyses suggest that all dyes showed a strong affinity to chitosan polymer chains, with the presence of extended hydrogen bonds and Van der Waals forces perturbing the chitosan network. Interestingly, very good results were obtained in recycling experiments related to the dyeing capacities of chitosan blended films in the presence of textiles. An ecofriendly application is thus presented in this paper. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45945.
      PubDate: 2017-11-12T07:56:14.13822-05:0
      DOI: 10.1002/app.45945
       
  • Melt compounded nanocomposites with semi-interpenetrated network structure
           based on natural rubber, polyethylene, and carrot nanofibers
    • Authors: Md. Minhaz-Ul Haque; Natalia Herrera, Shiyu Geng, Kristiina Oksman
      Abstract: The present study deals with the processing and characterization of cellulose nanocomposites natural rubber (NR), low-density polyethylene (LDPE) reinforced with carrot nanofibers (CNF) with the semi-interpenetrated network (S-IPN) structure. The nanocomposites were compounded using a co-rotating twin-screw extruder where a master-batch of NR and CNF was fed to the LDPE melt, and the NR phase was crosslinked with dicumyl peroxide. The prepared S-IPN nanocomposites exhibited a significant improvement in tensile modulus and yield strength with 5 wt % CNF content. These improvements are due to a better phase dispersion in the S-IPN nanocomposites compared with the normal blend materials, as demonstrated by optical microscopy, electron microscopy and ultraviolet–visible spectroscopy. The S-IPN nanocomposite also displayed an improved crystallinity and higher thermal resistance compared with NR, CNF, and the normal blend materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45961.
      PubDate: 2017-11-12T07:56:03.774367-05:
      DOI: 10.1002/app.45961
       
  • Addition flame-retardant effect of nonreactive phosphonate and expandable
           graphite in rigid polyurethane foams
    • Authors: Linjie Li; Yajun Chen, Lijun Qian, Bo Xu, Wang Xi
      Abstract: A series of flame-retardant rigid polyurethane foams (RPUFs) containing nonreactive phosphonate (5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl) methyl dimethyl phosphonate P-oxide (EMD) and expandable graphite (EG) were prepared by water blown. The flame-retardant properties and mechanism of EMD/EG on RPUFs were systematically investigated. The EMD/EG system effectively increased the limiting oxygen index (LOI) value and decreased the values of total heat release (THR), av-effective heat of combustion (EHC), pk-heat release rate (HRR), total smoke release (TSR) of RPUFs. The impact values of LOI, THR, and av-EHC resulted by EMD/EG system are nearly equal to the sum of the impact values by EMD and EG individually in RPUFs, which implies the addition flame-retardant effect from EMD and EG. EMD alone exerted excellent gas-phase flame-retardant effect by releasing PO fragments with quenching effect. The firm residue produced by EMD combined well with the loose and worm-like expanded graphite from EG further to form compact and expanded char layer, which brought excellent barrier effect and filtration effect to matrix. That's why pk-HRR and TSR values of RPUF reduced. Depending on the simultaneous actions of EMD/EG system in gas phase and condensed phase during combustion, the flame-retardant effects from nonreactive phosphonate and EG on RPUFs were added together. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45960.
      PubDate: 2017-11-12T07:55:48.300196-05:
      DOI: 10.1002/app.45960
       
  • The role of radical polymerization in the production of thermoregulating
           microcapsules or polymers from saturated and unsaturated fatty acids
    • Authors: Anna M. Szczotok; Manuel Carmona, Anna-Lena Kjøniksen, Juan F. Rodriguez
      Abstract: The microencapsulation of linoleic (LinA), oleic, erucic, and palmitic acids (PAs) from styrene and divinylbenzene were studied by using the suspension-like polymerization technique. All materials exhibited a spherical shape, with a particle size between 166 and 416 μm. The phase change material (PCM) content decreased with the presence of double bonds in the fatty acid molecule. The thermal energy storage (TES) capacity of the microcapsules (MC) containing saturated PA was the highest (123.30 J g−1). Whereas, the lowest TES capacity was observed for the LinA. TES capacity values from unsaturated fatty acid materials and the high particle yield indicated that these kinds of acids played two different roles, as PCM and also as monomers, in the radical polymerization processes. At high initiator concentrations, the unsaturated fatty acids were observed to react. This was confirmed by Fourier transform infrared where the peak assigned to the CC bond disappears in the spectrum of MC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45970.
      PubDate: 2017-11-12T07:55:41.692594-05:
      DOI: 10.1002/app.45970
       
  • Preparation and characterization of graphene reinforced PA6 fiber
    • Authors: Lian Tang; Yiren Li, Ye Chen, Peng Ji, Chaosheng Wang, Huaping Wang, Qing Huang
      Abstract: Here, we report the successful preparation of PA6/GO composite fibers through in situ polymerization and the melting spinning method. The results suggest that graphene has induced only minor changes on the relative viscosity yet exhibits significant effects on the crystallization characteristics. The SEM images of the fibers have shown several expended borders as a consequence of graphene addition. The maximum strength of the composite fibers (5.3 cN/dtex) has been reached 0.05 wt % graphene added to the system; the draw ratio was equaled to 3.8. Compared to the neat PA6 fiber, the fibers with graphene displayed superior creep resistance features; the creep rate constant was 0.38 at a 0.05 graphene concentration, with a draw ratio of 3.5. The approach employed in this research paves the way towards PA6/graphene nanocomposites have been prepared through in situ polymerization using caprolactam and graphene oxide/water pulp as starting materials. In situ polymerization approach facilitated a superior interaction between PA6 and graphene. Compared to graphene oxide powder, the graphene oxide in water pulp has prevented the agglomeration when added to the caprolactam melt, leading to its enhanced dispersion within the system. PA6/graphene as-spun fiber has been produced by the mean of melt-spinning strategy using a melt-spinning machine, obtaining products with different draw ratios after drawing at 120 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45834.
      PubDate: 2017-11-11T08:13:18.123839-05:
      DOI: 10.1002/app.45834
       
  • A novel ultra-low energy reverse osmosis membrane modified by chitosan
           with glutaraldehyde crosslinking
    • Authors: Bhargav B. Mehta; Rutvik N. Joshi, Hiren D. Raval
      Abstract: The energy consumption of reverse osmosis (RO) has declined significantly since inception and to further decrease the energy consumption is a challenging task. The present article demonstrates the novel method to increase the membrane productivity and reduce energy consumption of desalination. Thin film composite RO (TFC RO) membrane was subjected to 2000 mg/L sodium hypochlorite for 1 h followed by varying concentrations of chitosan and glutaraldehyde for 1 h each to make a hydrophilic supra-molecular assembly of linear polysaccharide over the polyamide layer. RO membrane exposed to 1000 mg/L chitosan and glutaraldehyde each reported 180% increase in water-flux with about 2.7% increase in divalent ion rejection as compared to virgin TFC RO membrane. The superior performance of the membrane was explained by increased hydrophilicity as shown by decline in contact angle from 46.37° to 29.87°, increase in surface area ratio from atomic force microscope image analysis, and modification in chemical structure of polyamide from attenuated total reflectance Fourier transform infrared spectroscopy. It was further investigated that curing of glutaraldehyde treated membrane resulted in decreased water-flux because of increase in crosslink density. Thus, an ultra-low energy RO process can be developed based on polyamide–chitosan–glutaraldehyde membrane. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45971.
      PubDate: 2017-11-10T05:06:02.697519-05:
      DOI: 10.1002/app.45971
       
  • Remendable polymers via reversible Diels–Alder cycloaddition of
           anthracene-containing copolymers with fullerenes
    • Authors: Julia Kötteritzsch; Robert Geitner, Johannes Ahner, Marcus Abend, Stefan Zechel, Jürgen Vitz, Stephanie Hoeppener, Benjamin Dietzek, Michael Schmitt, Jürgen Popp, Ulrich S. Schubert, Martin D. Hager
      Abstract: Poly(lauryl methacrylate)s with anthracene moieties in the side chain were converted with C60-fullerene and phenyl-C61-butyric acid methyl ester (PCBM), resulting in new remendable (self-healing) polymeric materials. The utilization of differently substituted anthracene monomers enabled the tuning of the reactivity and the resulting mechanical properties. Copolymers with different contents of the anthracene moieties were synthesized and characterized using size exclusion chromatography, 1H nuclear magnetic resonance (NMR) spectroscopy as well as differential scanning calorimetry (DSC). 1H NMR spectroscopic studies were utilized in order to investigate the reversibility of the Diels–Alder reaction between copolymers with C60-fullerene and PCBM, respectively, in solution. In order to investigate the conversion of the polymers with C60-fullerene and PCBM in bulk, additionally, DSC, nanoindentation, rheology, atomic force microscopy (AFM), 3D microscopy, simultaneous thermal analysis (STA) and FT-Raman investigations were performed. The fullerene-containing copolymers could be healed in a temperature range of 40–80 °C. Consequently, a new generation of low temperature remendable polymers could be established. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45916.
      PubDate: 2017-11-10T05:05:57.729436-05:
      DOI: 10.1002/app.45916
       
  • Thermal degradation and combustion behavior of intumescent flame-retardant
           polypropylene with novel phosphorus-based flame retardants
    • Authors: Lingang Lu; Nan Guo, Xiaodong Qian, Shousheng Yang, Xuebao Wang, Jing Jin, Gaosong Shao
      Abstract: The objective of this study was to develop an environmentally friendly fire-retardant polypropylene (PP) with significantly improved fire-retardancy performance with a novel flame-retardant (FR) system. The system was composed of ammonium polyphosphate (APP), melamine (MEL), and novel phosphorus-based FRs. Because of the synergistic FR effects among the three FRs, the FR PP composites achieved a V-0 classification, and the limiting oxygen index reached as high as 36.5%. In the cone calorimeter test, both the peak heat-release rate (pHRR) and total heat release (THR) of the FR PP composites were remarkably reduced by the incorporation of the novel FR system. The FR mechanism of the MEL–APP–FR–PP composites was investigated through thermogravimetric analysis and char residue characterization, and the results reveal that the addition of MEL–APP–FRs promoted the formation of stable intumescent char layers. This led to the reduction of pHRR and THR and resulted in the improvement of the fire retardancy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45962.
      PubDate: 2017-11-10T05:05:36.305897-05:
      DOI: 10.1002/app.45962
       
  • Enhanced antioxidant activity of fish gelatin–chitosan edible films
           incorporated with procyanidin
    • Authors: Sadykova Ramziia; Hui Ma, Yunzhen Yao, Kunrui Wei, Yaqin Huang
      Abstract: Gelatin and chitosan are edible polymers, which may be used in combination with antioxidant extracts as films to extend shelf life of foods. In this work, fish gelatin–chitosan edible films with procyanidin (PC) are successfully prepared. The effects of PC on the antioxidant, microstructure, physical properties, and antimicrobial activity of the films and solutions are studied. The results suggest that the addition of PC makes the gelatin–chitosan film possess the highest 2,2-azinobios-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity up to 95.63% at 1.00 mg/mL. As to mechanical properties, drop in tensile strength (27.17 ± 2.35%) and gain in elongation at break (33.42 ± 2.48%) are found for film with 1.00 mg/mL of PC. Owing to the simultaneous antioxidant and antimicrobial activities displayed for these films based on blends of gelatin and chitosan and additivated with PC could provide an alternative as active packaging material for food applications such as fish, meat, and cheese. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45781.
      PubDate: 2017-11-09T10:16:52.335906-05:
      DOI: 10.1002/app.45781
       
  • Fabrication of flexible transparent electrodes using PEDOT:PSS and
           application to resistive touch screen panels
    • Authors: Takeo Mochizuki; Yuki Takigami, Takahiro Kondo, Hidenori Okuzaki
      Abstract: The flexible transparent electrodes were fabricated by line patterning of conductive inks consisting of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonic acid) (PEDOT:PSS) water dispersion, ethylene glycol, isopropyl alcohol, and tetraethoxysilane (TEOS) on polyethylene terephthalate (PET) films. The values of sheet resistance (Rs), total light transmittance, haze, figure-of-merit, and pencil hardness of the PEDOT:PSS-TEOS/PET film were found to be 301 Ω/sq., 85.0%, 2.4%, 41, and 2H, respectively. Furthermore, a resistive touch screen panel was fabricated using the PEDOT:PSS-TEOS/PET film as the top electrode. It was found that the drawing on the resistive touch screen panel was successfully displayed on the PC screen with good in-plane uniformity and maximum linearity of 0.8%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45972.
      PubDate: 2017-11-09T10:16:02.414025-05:
      DOI: 10.1002/app.45972
       
  • Increased thermal stability of nanocellulose composites by
           functionalization of the sulfate groups on cellulose nanocrystals with
           azetidinium ions
    • Authors: Mikaela Börjesson; Karin Sahlin, Diana Bernin, Gunnar Westman
      Abstract: Cellulose nanocrystals (CNCs) prepared via sulfuric acid hydrolysis are decorated with sulfate groups that yield a stable water suspension. To make the CNCs adaptable for use in composites, the hydroxyl groups on the surface are usually hydrophobized. In this article, an alternative hydrophobization method is described in which the sulfate groups are conjugated with azetidinium salts. The results of this study show that the sulfate groups can be functionalized with azetidinium salts and from thermal studies, it was discovered that the functionalization led to a 100 °C increase in thermal stability, compared with unmodified CNCs. The nanocomposites prepared by extrusion of CNC-coated low-density polyethylene powder displayed similar mechanical properties as the CNC-reference sample, but without the discoloration, due to the increased thermal stability. In conclusion, the azetidinium reagent reacts preferentially with sulfate groups, and this new type of chemical conversion of sulfate groups on polysaccharides will be beneficial in nanocomposite manufacturing. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45963.
      PubDate: 2017-11-08T06:25:35.048424-05:
      DOI: 10.1002/app.45963
       
  • Nanoencapsulation of intercalated montmorillonite-urea within PVA
           nanofibers: Hydrogel fertilizer nanocomposite
    • Authors: Mohammad Hossein Azarian; Wan Ahmad Kamil Mahmood, Eunice Kwok, Wan Farahhanim Bt Wan Fathilah, Nor Fazilah Binti Ibrahim
      Abstract: This study describes the preparation and characterization of nanofibers with poly(vinyl alcohol) (PVA) as the wall matrix to encapsulate montmorillonite (MMT) clay and intercalated MMT-urea nanocomposite using an electrospinning technique. Nanofibers encapsulated with (1–5%, w/w) MMT clay were successfully produced and characterized in relation to morphological, spectroscopic, structural, surface, and thermal properties. The electrospinning conditions for voltage, flow-rate, and emitter to collector distance were 20 kV, 0.5, and 0.25 mL/h, and 10 cm, respectively. The surface roughness increased from 43.5 (empty fibers) to 56 nm in the PVA/MMT-3% and bead-less nanofibers were formed with the maximum diameter distribution and mean diameter value of 45–80 and 62 nm, respectively. The d-spacing was increased significantly from 1.004 in MMT to 1.684 nm in MMT-urea, indicating the intercalation of urea occurred successfully. Furthermore, elemental analysis results showed that the intercalated MMT-urea contained 30.4% nitrogen. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45957.
      PubDate: 2017-11-07T04:53:04.125656-05:
      DOI: 10.1002/app.45957
       
  • Removal of textile dyes from single and ternary solutions using
           poly(acrylamide-co-N-methylacrylamide) grafted katira gum hydrogel
    • Authors: Subinoy Jana; Jagabandhu Ray, Sunil K. Bhanja, Tridib Tripathy
      Abstract: A novel hydrogel poly(acrylamide-co-poly-N-methylacrylamide) grafted katira gum (KG) was synthesized via free radical copolymerization using a mixture of acrylamide and N-methylacrylamide in presence of N,N′-methylene-bis-acrylamide as a crosslinking agent. A series of hydrogels (KG-1 to KG-6) were prepared by varying amount of acrylamide and N-methylacryamide. Poly-acrylamide-g-katira gum (PAM-g-KG) and poly-N-methylacrylamide-g-katira gum (PNMA-g-KG) hydrogels were also prepared using same crosslinking agent. Swelling characteristics of all the prepared hydrogels in water were evaluated and the hydrogel with best swelling property (KG-6) was identified. The hydrogel KG-6 was characterized by FTIR, X-ray diffractometer, and scanning electron microscopy and was used for the adsorption of textile dyes namely methylene blue (MB), malachite green (MG), and congo red (CR) from single and ternary solutions. Adsorption dynamics, kinetics, isotherm, and thermodynamics of all the prepared hydrogels were studied in the ternary dye solutions. The sorption kinetics data were fitted well to pseudo-second order and the equilibrium adsorption data were found to follow Freundlich isotherm model. The thermodynamics studies showed that the adsorption process was spontaneous and exothermic in nature. The preferential dye adsorption by the hydrogel was followed in the order MB > MG > CR. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45958.
      PubDate: 2017-11-07T04:52:19.303473-05:
      DOI: 10.1002/app.45958
       
  • Biocompatible, stimuli-responsive hydrogel of chemically crosslinked
           β-cyclodextrin as amoxicillin carrier
    • Authors: Arpita Roy; Priti Prasanna Maity, Santanu Dhara, Sagar Pal
      Abstract: A novel pH-responsive, chemically crosslinked hydrogelator (cl-β-CD/pVP) has been fabricated using β-cyclodextrin (β-CD) and N-vinyl pyrollidone (N-VP) in presence of diurethane dimethacrylate (DUDMA) crosslinker/azobisisobutyronitrile initiator through free radical polymerization. Various grades of cl-β-CD/pVP have been synthesized and the best grade has been considered with higher crosslinking density, higher gel strength, and lower % swelling ratio. The hydrogelator has been characterized by FTIR, 1H and 13C NMR spectroscopy, TGA, and FESEM analyses. The hydrogelator demonstrates pH-responsive behavior, which has been confirmed by swelling behavior and gel characteristics at various pH (at 37 °C). Using hen egg lysozyme, degradation experiment has been performed, which confirms the biodegradable nature of the hydrogel. The in vitro cytotoxicity study and live–dead assay suggest that the hydrogelator is cytocompatible toward MG-63 cells. Finally, the hydrogelator shows excellent efficacy as an antibiotic (amoxicillin) carrier. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45939.
      PubDate: 2017-11-07T04:52:11.035167-05:
      DOI: 10.1002/app.45939
       
  • Fabrication of ceramic nanofibers using polydimethylsiloxane and
           polyacrylonitrile polymer blends
    • Authors: Saja Al-Ajrah; Khalid Lafdi, Yufei Liu, Philippe Le Coustumer
      Abstract: Nanofibers with several hundred of nanometers were successfully fabricated using electrospinning process and a mixture of two types of polymers which are: polydimethylsiloxane and polyacrylonitrile as precursors. After stabilization and carbonization at 1000 °C, three phases which are: silicon carbide (SiC), carbon, and oxy-SiC were presented. Spectroscopic and microscopic techniques had confirmed the presence of nanocrystalline SiC and turbostratic carbons. These phases formed an intertwined network at the nanometric scale. In addition, the resulted fibers showed a core-skin effect with skin richer in carbon and a core mainly dominated by silicon-based phases in the form SiC or SiOC ceramics. A significant improvement was observed in both tensile strength and elastic modulus in these hybrid fibers. In term of crystallography, these nanofibers seem to exhibit similar microstructure that was observed in Nicalon fiber. However, it was difficult to determine the ratio of these phases and their influence on the physical properties of these hybrid fibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45967.
      PubDate: 2017-11-07T04:51:05.78567-05:0
      DOI: 10.1002/app.45967
       
  • Preparation and characterization of a superabsorbent slow-release
           fertilizer with sodium alginate and biochar
    • Authors: M. Baki; J. Abedi-Koupai
      Abstract: A novel hydrogel was synthesized through the graft copolymerization of acrylic acid (AA) and acrylamide (AM) onto sodium alginate with ammonium persulfate as the initiator, methylene bisacrylamide as the crosslinking agent, and calcium chloride as the precipitating agent. Rapeseed meal biochar made at 300 °C was also used. A series of graft copolymers with various molar ratio of AA to AM was prepared. The structures of the hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The free absorbency and rate of release were investigated. The grafting efficiency increased as the concentration of AM increased. There was a considerable percentage of nitrogen in the graft copolymers, and the release rate of nitrogen from fertilizer in soil and water decreased with increasing concentration of AM. The water retention of soil without hydrogel remained at 63 and 53.4% on the 10th and 20th days, but with the hydrogels, it was above 70% even on the last day. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45966.
      PubDate: 2017-11-07T04:50:58.447301-05:
      DOI: 10.1002/app.45966
       
  • Thermal and fire behavior of isophorone diisocyanate based polyurethane
           foams containing conventional flame retardants
    • Authors: I. Eceiza; A. Barrio, L. Martín, M. A. Veganzones, M. J. Fernández-Berridi, L. Irusta
      Abstract: This work reports on the fire behavior of isophorone diisocyanate-based polyurethane foams containing different conventional flame retardants (FRs) such as melamine, ammonium polyphosphate, aluminum hydroxide, expandable graphite, and their combinations. The foams were obtained in a laboratory scale and characterized in terms of their morphology, density, thermal stability, and fire behavior. According to atomic force microscopy, the incorporation of FRs decreased the phase separated domain size. The cellular structure of the foams was examined qualitatively by scanning electron microscopy while the quantitative analysis of the surrounding skin was performed by optical microscopy and Image J. The FR containing foams showed more and smaller cells. The thermogravimetric analysis showed that the FRs had no influence in the initial degradation temperature of the foams. However, the obtained residue values were higher than the theoretical ones, indicating that there was some type of interaction between the FRs and the foams. The fire behavior of polyurethane foams was studied by the cone calorimeter and the data showed that the introduction of expandable graphite and combinations of ammonium polyphosphate/melamine to the reference foam gave rise to a significant reduction in the total heat release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45944.
      PubDate: 2017-11-07T01:51:56.708238-05:
      DOI: 10.1002/app.45944
       
  • Phosphate ester groups-containing ricinoleic acid-based Ca/Zn: Preparation
           and application as novel thermal stabilizer for PVC
    • Authors: Mei Wang; Jianchun Jiang, Jianling Xia, Shouhai Li, Mei Li
      Abstract: Phosphate ester groups containing ricinoleic acid-based Ca/Zn (LPPRA-Ca and LPPRA-Zn) stabilizer was successfully synthesized from ricinoleic acid (RA) and used as thermal stabilizers for poly(vinyl chloride) (PVC). These thermal stabilizers were characterized by Fourier transform infrared spectrometry, 1H nuclear magnetic resonance, and inductively-coupled plasma atomic emission spectroscopy. The effects of LPPRA-Ca/LPPRA-Zn, CaSt2/ZnSt2, and other stabilizers on the thermal stability of PVC were studied through Congo Red test, discoloration tests, thermogravimetric analysis (TGA), TGA–infrared, and TGA–mass spectrometry. The thermal stability tests show that LPPRA-Ca/LPPRA-Zn displays the best initial color stability and long-term thermal stability for PVC. The superior performance is attributed to the synergistic effect of LPPRA-Ca and LPPRA-Zn. Moreover, a lower Zinc content of LPPRA-Zn in PVC helps to decrease the “zipper dehydrochlorination” of the product, which contributes to a better initial thermal stability. Except for the better stabilization performance, LPPRA-Ca/LPPRA-Zn also displays better plasticization performance for PVC compared with other stabilizers. A possible stabilizing mechanism of PVC/LPPRA-Ca/LPPRA-Zn system was presented. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45940.
      PubDate: 2017-11-06T05:58:46.623489-05:
      DOI: 10.1002/app.45940
       
  • Evolution of morphology, ferroelectric, and mechanical properties in
           poly(vinylidene fluoride)–poly(vinylidene fluoride-trifluoroethylene)
           blends
    • Authors: G. Suresh; G. Mallikarjunachari, Sanjay Jatav, Ch. Thirmal, M. S. Ramachandra Rao, Dillip K. Satapathy
      Abstract: Considering the complementary properties of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)], it appears that their blends have the potential to be promising candidates for device applications. We report the evolution of morphology, ferroelectric, and mechanical properties (modulus and hardness) and their dependence on preparation temperature for PVDF–P(VDF-TrFE) blends. From ferroelectric hysteresis measurements it was found that P(VDF-TrFE) rich blends treated at higher temperature show significant values of remanent polarization. Remanent polarization values show a fourfold increase in these P(VDF-TrFE) rich blends treated at higher temperature. Interestingly, blends prepared from high temperature showed greater value of remanent polarization even though they were found to consist of smaller amount of electroactive phase as compared to their low temperature treated counterpart. Nanoindentation experiments revealed that high temperature treatment improves the modulus of blends by at least 100%. This report attempts to tie these findings to the morphology and crystallinity of these blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45955.
      PubDate: 2017-11-06T05:58:37.868432-05:
      DOI: 10.1002/app.45955
       
  • A synthesis study of phosphonated PSEBS for high temperature proton
           exchange membrane fuel cells
    • Authors: Vijayakumar Elumalai; Raja Annapooranan, Madhubala Ganapathikrishnan, Dharmalingam Sangeetha
      Abstract: A series of novel phosphonated proton exchange membranes has been prepared using poly(styrene-ethylene/butylene-styrene) block copolymer (PSEBS) as base material. Phosphonic acid functionalization of the polymer was performed by a simple two-step process, via chloromethylation of PSEBS followed by phosphonation utilizing the Michaels–Arbuzov reaction. The successful phosphonation of the polymers were characterized by NMR and Fourier transform infrared. The phosphonated ester form of the membranes were obtained by solvent evaporation method and hydrolyzed to get a proton conducting membrane. The membrane properties such as ion exchange capacity, water uptake and proton conductivity at various temperatures were examined for their suitability to be utilized as a high temperature polymer electrolyte. Additionally, the morphology, thermal, and mechanical properties of the synthesized membranes were investigated, using scanning electron microscope, thermogravimetric analysis, and tensile test, respectively. The effective (anhydrous) proton conductivity was studied with respect to various degrees of functionalization. From the studies, the membranes were found to have a comparatively good conductivity and one of the membranes reached the maximum value of 5.81 mS/cm2 at 140 °C as measured by impedance analyzer. It was found that the synthesized membranes were mechanically durable, chemically, and thermally stable. Hence, the synthesized phosphonated membranes could be a promising candidate for high temperature polymer electrolyte fuel cell applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45954.
      PubDate: 2017-11-06T05:57:50.472115-05:
      DOI: 10.1002/app.45954
       
  • Online prediction of the filtration performance of polypropylene melt
           blown nonwovens by blue-colored glow
    • Authors: Haifeng Zhang; Jinxin Liu, Xing Zhang, Chen Huang, Xiangyu Jin
      Abstract: In recently years, fine particulate matter (PM) pollution has drawn worldwide attention due to its serious threat to public health, visibility, climate, and ecosystems. The electret filter that can significantly improve the filtration efficiency without increasing the pressure drop has been widely used to for PM filtration. However, there were still some blind spots in the corona charging process, such as the interaction effects between the charging factors on the electret performances and the electric spark phenomenon during charging, which generate challenges for further improving the electret performance. Herein, we report an inconspicuous charging phenomenon that a blue-colored glow was observed during corona charging process. We named it as “Waterfall glow”, because a lot of charges appear to flow. The relationship between the blue-colored glow and the filtration efficiency was investigated. The results showed that the filtration performance of the electret melt blown was positively correlated to the intensity of blue-colored glow. The phenomenon enables us to online predict the filtration performance of the electret material in the actual production. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45948.
      PubDate: 2017-11-03T12:15:53.448034-05:
      DOI: 10.1002/app.45948
       
  • Roll-to-roll printed carbon nanotubes on textile substrates as a heating
           layer in fiber-reinforced epoxy composites
    • Authors: Thomas Fischer; Julia Rühling, Nora Wetzold, Tino Zillger, Thomas Weissbach, Thomas Göschel, Matthias Würfel, Arved Hübler, Lothar Kroll
      Abstract: The performance of wind turbines suffers from icing in regions with extreme climate. One approach is to incorporate heating elements into the most susceptible areas of the wind turbine blade as protection against icing and for de-icing. Cost-efficient and reproducible fabrication, as well as easy integration is important due to the large area of wind turbine blades. In this work, multi-walled carbon nanotubes are applied on a 50% poly(ethylene terephthalate) and 50% polyamide non-woven textile substrate by rotary-screen printing. The printed layers function as resistive heating elements in a fiber-reinforced composite. The heating areas are provided with flexographic or screen inline-printed silver-electrodes and can be integrated by means of vacuum infusion into a glass fiber-reinforced epoxy composite laminate. These laminates, which are connected to an intelligent electrical control system, are suitable for melting ice on the surface of components or for preventing the formation of ice. The first promising experiments on heating structures in a rotor blade of a wind turbine at laboratory scale (2 m length) are the basis of studies on intelligent electrical control of heating structures and their behavior at different temperatures. The heating elements were able to melt a 3–4 mm thick ice layer within 25 min in a climate chamber at −5 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45950.
      PubDate: 2017-11-03T12:15:46.60886-05:0
      DOI: 10.1002/app.45950
       
  • Tuning the gas separation performance of fluorinated and sulfonated PEEK
           membranes by incorporation of zeolite 4A
    • Authors: Zaman Tahir; Ayesha Ilyas, Xianfeng Li, Muhammad Roil Bilad, Ivo F. J. Vankelecom, Asim Laeeq Khan
      Abstract: Mixed matrix membranes (MMMs) containing fluorinated-sulfonated poly(ether ether ketone) (F-SPEEK) and zeolite 4A filler, were prepared by solution casting. F-SPEEK with a fixed degree of sulfonation (40%) was used for membrane synthesis. The SEM pictures showed good interfacial adhesion between filler particles and polymer, which was also confirmed by the increase in glass transition temperature of MMMs with increase in filler particles. Pure and mixed gas permeation experiments were carried out to investigate the potential of this membrane material. The results revealed that addition of zeolite 4A fillers enhanced both permeability and selectivity owing to the intrinsic nature of polymer and modified membrane morphology due to filler. The highest permeability obtained for CO2 at 30% filler loading was 49.2 Barrer, while highest selectivities obtained for CO2/CH4 and CO2/N2 were 55 and 58 compared to 47 and 51 for the unfilled polymer, respectively. Intrinsic CO2 solubility of F-SPEEK was observed to be decreased from 10.7 to 1.9 (10−2) cm3 (STP)/cm3 cmHg with the addition of Zeolite 4A. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45952.
      PubDate: 2017-11-02T08:16:55.024978-05:
      DOI: 10.1002/app.45952
       
  • Effects of nonionic surfactants and external factors on stability of latex
           in cement paste
    • Authors: Dongdong Han; Weideng Chen, Shiyun Zhong, Yan He
      Abstract: To clarify why different surfactants affect stability of latex in cement paste and why many latexes qualified in standard stability test still coagulate when mixed with cement, several kinds of nonionic surfactants with different structures were selected to improve stability of latex and the interactions among cement, latex, and surfactant were discussed. Results show that a higher affinity of surfactant to polymer contributes to a higher stability of latex in cement paste. When surfactants have similar hydrophilic group with each other, surfactants with phenyl in hydrophobic group can more effectively improve stability of styrene–acrylate (SA) latex in cement paste than that with n-alkyl. With the same hydrophobic group (octyl phenyl) in molecules, surfactants with shorter hydrophilic group show better stabilization effect on SA latex. The combined action of high Ca2+ concentration, high solid concentration, and mechanical shear during agitation process of cement paste is the decisive factor causing coagulation of latex. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45946.
      PubDate: 2017-11-02T08:16:49.703787-05:
      DOI: 10.1002/app.45946
       
  • Unique crystallization behavior of isotactic polypropylene in the presence
           of l-isoleucine and its inhibition and promotion mechanism of nucleation
    • Authors: Xiaoshan Peng; Zhong Xin, Shicheng Zhao, Shuai Zhou, Yaoqi Shi, Chunlin Ye
      Abstract: l-Isoleucine (l-Ile) was identified as an efficient anti-nucleating agent for isotactic polypropylene (iPP). At 0.08 wt %, l-Ile could significantly decrease the peak crystallization temperature (Tcp) of iPP by up to 8 °C at a cooling rate of 20 °C/min. Furthermore, l-Ile exhibited both anti-nucleation and pro-nucleation abilities; i.e., a low content of l-Ile inhibited iPP crystallization, whereas a high content promoted iPP crystallization. The unique crystallization behavior of iPP in the presence of l-Ile was investigated by differential scanning calorimetry, polarized optical microscopy (POM), and rheological measurement. According to POM, a low content of l-Ile completely dissolved in the iPP melt, whereas a high content of l-Ile did not. Therefore, a mechanism by which l-Ile inhibits and promotes the nucleation of iPP was proposed. Dissolving l-Ile molecules in the iPP melt hindered the homogeneous nucleation of iPP as a “dilution effect”; however, as the content increases, l-Ile could not be completely dissolved in molten iPP, and the residual crystals of l-Ile thus provided heterogeneous nucleation sites for iPP and further promoted its crystallization. Experimental evidence from rheology and POM supported this mechanism. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45956.
      PubDate: 2017-11-02T08:16:44.965315-05:
      DOI: 10.1002/app.45956
       
  • Nanofibrous nonwovens based on dendritic-linear-dendritic poly(ethylene
           glycol) hybrids
    • Authors: Stefanos Kikionis; Efstathia Ioannou, Oliver C. J. Andrén, Ioannis S. Chronakis, Amir Fahmi, Michael Malkoch, Georgios Toskas, Vassilios Roussis
      Abstract: Dendritic-linear-dendritic (DLD) hybrids are highly functional materials combining the properties of linear and dendritic polymers. Attempts to electrospin DLD polymers composed of hyperbranched dendritic blocks of 2,2-bis(hydroxymethyl) propionic acid on a linear poly(ethylene glycol) core proved unsuccessful. Nevertheless, when these DLD hybrids were blended with an array of different biodegradable polymers as entanglement enhancers, nanofibrous nonwovens were successfully prepared by electrospinning. The pseudogeneration degree of the DLDs, the nature of the co-electrospun polymer and the solvent systems used for the preparation of the electrospinning solutions exerted a significant effect on the diameter and morphology of the electrospun fibers. It is worth-noting that aqueous solutions of the DLD polymers and only 1% (w/v) poly(ethylene oxide) resulted in the production of smoother and thinner nanofibers. Such dendritic nanofibrous scaffolds can be promising materials for biomedical applications due to their biocompatibility, biodegradability, multifunctionality, and advanced structural architecture. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45949.
      PubDate: 2017-11-02T08:16:33.129363-05:
      DOI: 10.1002/app.45949
       
  • Building and origin of bio-based bismaleimide resins with good
           processability, high thermal, and mechanical properties
    • Authors: Meiying Ge; Jia-Tao Miao, Li Yuan, Qingbao Guan, Guozheng Liang, Aijuan Gu
      Abstract: Bio-based high performance thermosetting resins have been urgently required by cutting-edge fields for meeting sustainable development. A new kind of high performance thermosetting resins (BA-n) with good processability, high thermal resistance, and mechanical properties was developed based on 4,4′-bismaleimidodiphenylmethane (BDM) and renewable bis(5-allyloxy)-4-methoxy-2-methylphenyl)methane (ABE) from bio-based lignin derivative. The effect of the molar ratio of allyl to imide (n) on structures and properties of BA resins were systematically researched. BA-n resins have much better processability, thermal, and mechanical properties than their petroleum-based counterparts, 2,2′-diallylbisphenol A-modified BDM (BD-n) resins. Compared with BD-0.86, the best available bismaleimide (BMI) resin, BA-0.86 not only has 6 h longer process window and 13.7 °C higher glass transition temperature, but also owns the highest flexural strength and modulus among all bio-based allyl compound-modified BMI resins reported. The origin behind these attractive performances of BA resins is revealed by discussing the unique crosslinked structure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45947.
      PubDate: 2017-11-02T08:16:20.713205-05:
      DOI: 10.1002/app.45947
       
  • Soy protein isolate nanocomposite film enriched with eugenol, an
           antimicrobial agent: Interactions and properties
    • Authors: Samira Fernandes Nassar; Clara Dombre, Emmanuelle Gastaldi, François Touchaleaume, Pascale Chalier
      Abstract: Nanocomposites films were designed from soy protein isolates (SPI), clays (Na+-MMT), and eugenol an antimicrobial agent. Interactions between Na+-MMT and eugenol were evidenced by a shift of the d-spacing by X-ray diffraction analysis. The addition of Na+-MMT (5 and 7.5% w/w) in SPI solution increased its shear thinning behavior and its consistency. Accordingly, a good exfoliation of clays in SPI films was observed. The glass transition temperature of SPI films was impacted by the clays addition but not the water vapor permeability. In contrast, the addition of eugenol in SPI solution did not affected the consistency but induced a decrease of the SPI film Tg and an increase of the water vapor permeability. The presence of eugenol counterbalanced the effect of clays on consistency of film-forming solution. The clay intercalation process was facilitated and the water vapor permeability and active agent release were modified. The presence of clay did not affect the antibacterial effect of eugenol/SPI films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45941.
      PubDate: 2017-11-02T08:16:10.068838-05:
      DOI: 10.1002/app.45941
       
  • High cycling stability and well printability
           poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/multi-walled
           carbon nanotube nanocomposites via in situ polymerization applied on
           electrochromic display
    • Authors: Ting Chen; Qifeng Chen, Guhong Liu, Guangxue Chen
      Abstract: A high cycling stability material and an additive manufacturing method are reported for the fabrication of solid electrochromic devices. The poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/multi-walled carbon nanotube (PEDOT:PSS/MWCNT) nanocomposites were synthesized via in situ polymerization. A carboxymethyl cellulose gel was used as the ink vehicle for screen printing. The electrochromic (EC) performance of films patterned by screen printing was also examined. The results of characterization indicate that strong interfacial interactions occurred between PEDOT:PSS and the MWCNTs and the MWCNTs formed a network in these conducting polymers film, so the composite was more conductive than pure PEDOT:PSS. Devices containing PEDOT:PSS/MWCNTs were more stable after 1000 cycles, exhibited higher rate of ion exchange and faster increases in current. The composite containing 0.3 wt % MWCNTs also had a 23% higher color contrast (ΔE*) than pure PEDOT:PSS at 2.5 V applied voltages. The EC inks with well printability not only can be used to print large area films, but also can print fine lines and pixel-type dots in displays. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45943.
      PubDate: 2017-10-31T08:55:46.628492-05:
      DOI: 10.1002/app.45943
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.196.182.102
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016