Authors:Krzysztof J. Wilczyński; Andrzej Nastaj, Krzysztof Wilczyński Abstract: A new computer model has been developed to simulate a starve-fed single-screw extrusion process of polymer blends. This is a composite model, which is based on combining melt conveying models with new fusion models for polymer blends. The model is able to predict pressure and temperature profiles, filling of the screw and rate of polyblend fusion. Computer calculations were executed for extrusion of high-density polyethylene and polystyrene blend at various technological conditions, and fill factor, pressure, temperature, and fusion profiles were calculated. The results of simulation studies were verified by experiment. PubDate: 2017-08-11T00:15:51.70099-05:0 DOI: 10.1002/adv.21873
Authors:Elzbieta Bociaga; Monika Kula, Konrad Kwiatkowski Abstract: The investigations of the change in properties and structure of polypropylene injection-molded parts, arising from cyclic loading, are presented. The strain–stress characteristics were determined in the cyclic tensile tests, at a fixed stress or deformation level. Experiments showed that cyclic loading causes some changes in structure and mechanical properties of polypropylene samples. Smaller total strain of samples and increase in Young's modulus after each consecutive ten cycles of loading were observed as the result of loading at a fixed stress level. In experiments carried out at the fixed strain level, the width of the loop decreases with the increase in number of cycles that indicates the material strengthening. Microscopic examinations showed the change in the structure of injection-molded parts after cyclic loading. The transient zone, occurring in the area of high shear stress between the core and the skin, became significantly wider for cyclically loaded parts. Phase changes in the part structure were investigated using WAXS method. Samples exhibited the difference in the content of polypropylene polymorphic modifications between the core and skin layers. In the skin, both for nonloaded and loaded parts, the presence of β-phase was confirmed, whereas this phase did not occur in the core. The investigation by DSC method demonstrated a small change in the degree of crystallinity in the sample core after 4,000 cycles of loading, while in the skin layer, the degree of crystallinity was reduced by about 2% when compared to the value obtained for samples after one loading cycle. PubDate: 2017-07-31T07:21:33.375237-05: DOI: 10.1002/adv.21872
Authors:Mohamed Elkasaby; Hussien A. Hegab, Atef Mohany, Ghaus M. Rizvi Abstract: The electrospun fibers can have applications in diverse fields, such as tissue scaffolds, optical electronics, nanocatalysis, and sound absorption. Nanoscale fibers with a higher surface area can provide superior mechanical, physical, and thermal properties. Therefore, investigation of the factors affecting the electrospinning process, for various materials, is required. In this study, the design of experiments issued for optimization of electrospinning of polyvinyl alcohol (PVA). Analysis of variance (ANOVA) and the Taguchi orthogonal array L27OA are employed to analyze the influence of process control parameters. The variables studied are the applied voltages, solution concentrations, rotational speeds, collecting distances, and flow rates. A mathematical model of the polymer fiber diameter as a function of significant process parameters has been built using response surface methodology (RSM). The concentration percentage and the flow rate were determined to be the most significant process variables at 99% and 90% confidence levels, respectively. The predictive model provides 84.34% average model accuracy, which is considered acceptable as this study deals only with 27 of 243 trials needed for a full study based on principles of design of experiments. An additional ANOVA test and corresponding mathematical model have been developed to obtain the interaction effects for processing parameters. PubDate: 2017-07-24T01:11:01.967078-05: DOI: 10.1002/adv.21869
Authors:Wael H. Eisa; Tarob Abdelnaby, Shahenda Mostafa, Mohamed Y. Elzayat Abstract: Chitosan-stabilized gold nanoparticles (Cs/Au) film was prepared by casting strategy without a need for reducing and/or stabilizing agents. The shape, size, and crystalline phase were studied using UV-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The nature of the interaction between the Cs and Au nanoparticles was studied using the Fourier transformer infrared (FTIR) spectroscopy. The as-prepared Cs/Au nanocomposite film showed high activity in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of an excess amount of NaBH4. Furthermore, the Cs/Au film is easily separable, as well as remains active after reused for 3 times. The Cs/Au nanocomposite film could be a promising candidate for various catalytic reactions. PubDate: 2017-07-24T01:06:31.935048-05: DOI: 10.1002/adv.21867
Authors:Mohamed Mohamady Ghobashy; Ghada Bassioni Abstract: Cross-linking of superabsorbent hydrogels based on poly(acrylamide-co-sodium alginate) is carried out using 60Co γ-radiation. Hydrogels of PAM/NaAlg with 1.5:0.5 and 1.0:1.0 w/v concentrations showed good gel contents of 87 and 66 (%) and swelling degrees in water of 3.7 and 5 (g/g) after 40 min, respectively. The chemical structure of the hydrogel is confirmed by FTIR, XRD, and ESR. The morphology of the hydrogel is observed using scanning electron microscopy. Intramolecular H-bonding in the hydrogel network is confirmed by TGA and DSC. The pH-responsive swelling behavior of (PAM-co-NaAlg) hydrogels is tested in different pH ranges showing higher swelling capacities in basic than in acidic media. This property proposes the use of (PAM-co-NaAlg) hydrogel as internal curing agent for concrete. The hydrogel is examined with cement weight ratios of (0.1–0.5) wt%. The study shows that cement with (PAM-co-NaAlg) hydrogel improves the compressive strength of cement at 0.1 and 0.2 wt%. PubDate: 2017-07-20T00:26:37.158011-05: DOI: 10.1002/adv.21870
Authors:Na Lu; Mei Shen, Zhanfeng Hou, Prakashan K, Zhenxiang Xin Abstract: Antioxidants are customarily used in elastomer compounds to enhance the service life of vulcanizates enduring high temperatures, but proper selection and dosage of the antioxidant is critical to obtain maximum beneficial effect. In this study, the effectiveness of several commercially available antioxidants on the performance of a resin-cured bromobutyl rubber (BIIR) vulcanizate was investigated. The antioxidants investigated belonged to different chemical classes such as p-phenylene diamine (antioxidant 4010NA), secondary amine (antioxidant 445), quinoline (antioxidant RD), and phenolic (antioxidants BHT, 1010, and 2246). The physicomechanical properties of the BIIR vulcanizates containing the various antioxidants were tested at room temperature, at higher temperatures, after subjecting to heat aging, and after storage. The results show that the physicomechanical properties of the BIIR vulcanizate severely deteriorate when antioxidant 4010NA is used. Among the other antioxidants used, the phenolic-type antioxidant BHT is found to be better for the resin-cured BIIR vulcanizate of this study. PubDate: 2017-07-18T22:45:30.183165-05: DOI: 10.1002/adv.21865
Authors:Toshitaka Kanai; Youhei Kohri, Tomoaki Takebe Abstract: The theoretical analysis of the spunbond process was set up and applied to polypropylene (PP) and its blends. The effect of blending low tacticity polypropylene (LMPP) to high tacticity PP on the spinnability of the spunbond process was investigated. A small amount of LMPP was found to stabilize the high-speed spinning of PP, and very fine fibers were obtained. From the calculated results, it was speculated that the improvement of spinnability originated from the suppression of crystallization speed and strain rate in the spinning process. The physical properties of the spunbond nonwoven fabrics were also investigated. PubDate: 2017-07-17T00:40:56.020405-05: DOI: 10.1002/adv.21866
Authors:Casparus Johannes Reinhard Verbeek; Aaron Low, Mark Christopher Lay, Talia Maree Hicks Abstract: Bloodmeal is a protein-rich coproduct of the meat industry and can be converted into a thermoplastic. A solution of peracetic acid can be used to degrade colored compounds in bloodmeal, yielding a light yellow material. This causes an increase in β-sheets in the protein's secondary structure, but the addition of sodium dodecyl sulfate (SDS) and triethylene glycol (TEG) reduced α-helical and β-sheet content, thereby increasing random coils. Without SDS, chains were less capable of folding into these structures, preventing sufficient intermolecular interactions and chain entanglement, leading to low specific mechanical energy input (SME) during extrusion, and poor consolidation. The whiteness of molded samples showed no correlation with SME during extrusion or the degree of consolidation after extrusion; however, they were observed to have a higher level of whiteness with increasing TEG content and should be considered as a secondary process not directly linked to extrusion. Increasing the amount of water during extrusion increased the Young's modulus (E) by facilitating formation of new interactions, while increasing TEG decreased E as a result of plasticization. The action of SDS on destabilizing electrostatic and hydrophobic interactions was beneficial to extrusion, although it had no further effect during injection molding. TEG had virtually no effect on tensile strength, although it was required for flow and facilitated the formation of strong interactions after water had been evaporated during conditioning. PubDate: 2017-07-16T23:00:38.071287-05: DOI: 10.1002/adv.21868
Authors:Fatma Walha; Khalid Lamnawar, Abderrahim Maazouz, Mohamed Jaziri Abstract: The purpose of the present work is to develop a new biomaterial with suitable melt strength, stiffness-to-toughness balance, and the required thermal performance for food packaging applications. The study is dedicated to investigating a new physical compatibilization approach of biosourced materials as well poly (lactic acid) (PLA) and polyamide 11 (PA11) in comparison with the chemical compatibilization through addition of a multifunctionalized epoxide. For this reason, this paper deals with gaining better understanding physical compatibilization in the biosourced blend with the incorporation of an acrylic melt strength enhancer into PLA/PA11 blend. The main focus of this paper is studying how physical compatibilization improves melt strength in comparison with chemical approach. Hitherto, the chain extension–branching balance was demonstrated to be difficult to be controlled and decoupled from chemical compatibilization at the polymer–polymer interface. Hence, the physical approach is presented as an original route in this work to develop a PLA-based blend with good film blown processability and engineering properties. Morphological, rheological and thermomechanical properties of the new obtained biosourced blends were studied. The physical compatibilization effect was confirmed by the tuning interfacial properties. The extensional rheology highlighted that melt strength for the physical blends was also improved without any pronounced strain hardening in comparison with reactive blends. Besides, a great enhancement of the blowing processing windows of physically PLA-PA11 compatibilized blend was highlighted while higher blow-up ratio and take-up ratio values were obtained. Overall, a correlation between the obtained thermal and crystalline properties was performed for the optimal biosourced blown film. PubDate: 2017-07-12T23:30:45.0946-05:00 DOI: 10.1002/adv.21864
Authors:Marina Fernandes Cosate de Andrade; Gustavo Fonseca, Ana Rita Morales, Lucia Helena Innocentini Mei Abstract: This work studied the commercial chain extender effectiveness on the mechanical recycling simulation of a pristine PLA using a single-screw extruder. We processed the material by two extrusion cycles to simulate a recycling process. In the second extrusion, part of the material was processed with chain extender and we evaluated its molecular weight, thermal degradation, melt flow index (MFI), thermal transitions, and mechanical properties. The molecular weight for the extruded neat PLA decreased and the MFI and crystallinity degree increased while the mechanical properties worsened. The onset thermal degradation occurred at lower temperature for the processed material. With the introduction of the chain extender, there was a recovery of properties with the increase in the polymer molecular weight, decrease in the MFI and crystallinity degree, and an improvement in both thermal stability and mechanical properties in relation to recycled PLA without this component. PubDate: 2017-07-12T03:45:38.149453-05: DOI: 10.1002/adv.21863
Authors:Yongqiang Lan; Weihong Wang Abstract: In this study, three kinds of biomass materials (lodgepole pine bark, larch wood, larch bark) were used to prepare biochar (BB), and the prepared products as fillers were mixed with polydimethylsiloxane (PDMS) for preparing composite membranes which were used for separating ethanol from water by pervaporation (PV). In accordance with the experiment results, the lodgepole pine bark BB was the best filler for the selective membrane to ethanol. The silane coupling agents NH2(CH2)3Si(OC2H5)3 (KH-550) and CH2=CH-Si(OCH3)3 (YDH-171) were applied in the modification of lodgepole pine bark BB. And the separation performances of the BB/PDMS composite membranes were researched in detail. The results showed that the permeability (flux and separation factor) of composite membranes has been significantly improved with the addition of modified BB. YDH-171 was more effective than KH-550. The optimum PV performances (the separation factor 11.3 and the corresponding flux 227.25 g m−2 h−1) were obtained by adding 3 wt. % modified BB for a 10 wt. % and 40°C ethanol solution. This study indicated the potential application of BB nanoparticles in preparing pervaporation separation membrane. PubDate: 2017-07-10T01:22:52.591814-05: DOI: 10.1002/adv.21856
Authors:Dasari Subramaniyam Karuna; Grace Rathnam, Udhumansha Ubaidulla, Mani Ganesh, Hyun Tae Jang Abstract: This study investigates the preparation of colon specific drug delivery of diclofenac sodium (DS) using maltiparticulate system with chitosan phthalate (CP). Technique adopted to prepare sphere shaped multiparticulate system was extrusion and spheronization. The prepared pellets resulted with good spherical geometry with 1.1 ± 0.20 mm diameter. DS loaded system shows a maximum delivery pH of 7.4 and the same depressed at pH 1.2. The developed system significantly (p PubDate: 2017-07-08T02:35:34.66718-05:0 DOI: 10.1002/adv.21859
Authors:Mohamed R. El-Aassar; Mamdouh S. Masoud, Marwa F. Elkady, Ahmed A. Elzain Abstract: Poly (Styrene-co-Acrylonitrile) (poly (St-co-AN) copolymer nanoparticles with controllable size are synthesized by a simple and cheap precipitation polymerization technique of styrene (St) and acrylonitrile (AN) monomers in aqueous medium using potassium persulfate (KPS) redox initiation system. Preparation of poly (St-co-AN) and studying all the parameters affecting the polymerization process such as time, temperature, monomer ratio, initiator molarity, cosolvent ratio, and solvent were considered. The resultant poly (St-co-AN) was compared with other studies which used different comonomers with AN, the comparison was assessed by evaluating the polymer conversion yield side. Maximum polymerization conversion yield, 66.5%, was obtained with St:AN (30%:70%) comonomer ratio. The smallest particle size obtained with this method was close to 16.17 nm and controlled by variation in polymerization conditions. The structure of poly (St-co-AN) copolymers were confirmed by Fourier transform infrared (FTIR), thermo gravimetric analysis (TGA), and differential thermal analyzer (DTA). The morphological structure of the copolymer particles was indicated by scanning electron microscope (SEM) photographs. The polymeric particle size was studied using particle size analyzer. PubDate: 2017-07-03T23:30:54.366179-05: DOI: 10.1002/adv.21860
Authors:Syed Nabeel Ahmed; M.N. Prabhakar, Siddaramaiah, Jung-IL Song Abstract: The versatility of the fiber reinforced composites has significantly replaced some of the sophisticated metal components in certain sectors of industries. The matrix could be altered to improve self-properties via silane modifiers by forming chemical linkages with the matrix in harmony with the reinforcing agents. This research work is an endeavor to enhance the traits of Vinyl ester by scrutinizing the influence of silane chemical agents using Hexamethyldisiloxane (HMDS). The dispersion time and concentration of these chemicals in matrix were optimized and henceforth a natural reinforcement, Abaca fabric was incorporated to constitute Natural fiber composite via Vacuum Assisted Resin Transfer Molding (VARTM) technique. The effect of resin modification on mechanical, thermal, and physical properties of Vinyl ester/Abaca (VE/AF) composite was examined. HMDS resin modified composite showed an improvement in the mechanical and flame retardant properties when compared to the pristine composite due to the formation of siloxane bonding which is compatible with the functional groups of both the matrix and the fabric. FT-IR and FESEM characterizations have showed imperative evidences to support the results. This investigation provides a channel for enhancing the properties of natural fiber composites via chemical modification technique. PubDate: 2017-07-03T03:21:46.995383-05: DOI: 10.1002/adv.21855
Authors:Fatih Biryan; Kadir Demirelli Abstract: The 4-(2-bromoisobutyroyl methyl)styrene [BBMS] monomer was synthesized. The homopolymer of BBMS was prepared by free radical polymerization method. The decomposition behavior of P(BBMS) was thermally investigated by thermogravimetric analysis (TGA). For thermal decomposition kinetics of poly(BBMS), Flynn–Wall–Ozawa method was applied to thermogravimetry curves. The first step, which is one of the two decomposition stages, is comprehensively related to elimination of hydrogen bromide and the other step is related to a multi-step process. The activation energy (Ea) of thermal decomposition of the first step and 50% weight loss is 148.5 and 190.7 kJ/mol, respectively. The results showed that the side group elimination without chain breaking comprehensively proceeded at lower temperature, and at progressive temperatures subsequently the specific chain scission did so. Degradation of poly(BBMS) did not lead to depolymerization. 1H, 13C-NMR, and FT-IR analyses showed that the decomposition products during degradation of poly(BBMS) to 260°C were comprehensively HBr and methacrylic acid. Electrically conducting graphene-based poly(BBMS) composites were prepared. The DC and AC electrical measurements of graphene-based poly(BBMS) composites were carried out. The AC dielectric measurements of poly(BBMS) were investigated up to 70°C between 100 Hz and 20 kHz depending on the alternating current conductivities. The dipolar functional groups (C–O, C=O, and Br) of the BBMS segment possesses significantly affect the dielectric constant. Also, the activation energy profile of different graphene/poly(BBMS) composites were revealed by measuring DC conductivity of individual composite material. PubDate: 2017-07-03T02:55:58.349377-05: DOI: 10.1002/adv.21858
Authors:Mohaddeseh Najafi; Morteza Sadeghi, Ali Bolverdi, Mahdi Pourafshari Chenar, Majid Pakizeh Abstract: In this study, the effects of silica nanoparticles on the permeability of pure CO2, O2, and N2 gases in cellulose acetate (CA) membrane have been studied. Silica particles were prepared via the sol–gel method through the hydrolysis of tetraethyl orthosilicate (TEOS). CA and CA/silica nanocomposite membranes were prepared by thermal phase inversion method. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transfer infrared (FTIR) analyses were employed to characterize the CA and CA/silica nanocomposite membranes. Gas permeation experiments showed an increase in the permeability of CO2 from 6.32 to 7.3 barrer and a reduction in the permeability of N2 from 0.18 to 0.09 barrer with the increment in silica content of the prepared composite membranes up to 20 wt%. Therefore, CO2/N2 selectivity of the nanocomposite membranes increased by increasing the silica content in the polymer matrix from 30 to 80 for 20 wt% load of silica. PubDate: 2017-06-29T06:45:49.350803-05: DOI: 10.1002/adv.21862
Authors:Thitikan Khampieng; Vipawee Yamassatien, Pongpol Ekabutr, Prasit Pavasant, Pitt Supaphol Abstract: Protein adsorption is the first phenomenon that occurs when foreign materials are inserted into the body. Materials used in biomedical applications can have different surface topologies. Knowledge of the effect of the surface on protein adsorption is important due to its influence on cell behavior. The main objective of this study was to analyze polycaprolactone (PCL) films with different surface topologies. Protein adsorption was studied using bovine serum albumin (BSA) as the biomolecule. Different surface topologies of PCL were induced by phase separation using solvents with various solubility parameters. The investigated solvents were chloroform, acetone, tetrahydrofuran (THF), and ethanol (EtOH). The PCL films with different surface topologies and protein-adsorbed PCL films were studied with respect to their hydrophobicity, the concentration and nature of functional groups on their surface, their surface roughness, and their cytotoxicity. Atomic force microscopy revealed that the films with the roughest surface were cast from 40:60 EtOH:THF and contained significantly larger amounts of adsorbed protein. Proteins preferentially adsorbed onto rough surfaces. The cell culture also indicated that mouse-calvaria-derived pre-osteoblastic cells proliferated best and exhibited the greatest amount of calcium deposition on the surface with the largest amount of adsorbed protein. PubDate: 2017-06-27T23:16:33.662345-05: DOI: 10.1002/adv.21861
Authors:Ewelina Pabjańczyk-Wlazło; Paulina Król, Izabella Krucińska, Michał Chrzanowski, Michał Puchalski, Grzegorz Szparaga, Sławomir Kadłubowski, Maciej Boguń Abstract: Studies related to selection of molar mass of hyaluronic acid and analysis of rheological properties of hyaluronic acid solutions modified with bioactive substances, used in spinning, were undertaken within the presented work. A cephalosporin group antibiotic, Biofuroxime®, was used, together with the nanoadditives zinc oxide (ZnO) and hydroxyapatite (HAp). Electrospinning studies were performed on selected solutions using a large scale laboratory station, allowing the process to be performed using three nozzles supplying the spinning solution. Optimum electrospinning conditions were selected on the basis of the performed study, which allow fibrous structures made of elementary fibres with diameters below 200 nm to be obtained. Studies showed that the most preferred distance between the nozzle and the collecting manifold was 450 mm and the most preferred applied voltage was 30 kV. The obtained, modified nanofibres of hyaluronic acid comprise structures for use in the production of biomaterials with a wide range of applications in tissue engineering. PubDate: 2017-06-25T23:24:32.751102-05: DOI: 10.1002/adv.21851
Authors:Milad Asgarpour Khansary; Mohammad Ali Aroon, Azam Marjani, Saeed Shirazian Abstract: During the fabrication procedure of polymeric membranes using nonsolvent induced phase inversion technique, thickness and weight of the polymeric cast film change rapidly. The only available guideline just presents a qualitative criterion for thickness change in which “penetration of the denser species into the film and the elimination of the lighter ones from film to coagulation bath” have been related to the densification of the cast solution and its thickness reduction. While it is well-suited for cellulose acetate/acetone/water ternary system, it is not applicable to our investigated systems, that is, polyethersulfone/n-methyl-pyrolidine/water and polysulfone/N-methylpyrrolidone/water. Thus, here the thermo-kinetic behavior of NIPS process was discussed, and then a thermodynamic model was developed, in which only initial cast film and final membrane properties were used as inputs. Two new simple suppositions were derived and examined. The use of thermodynamic modeling approach results in desirable estimation of overall changes, and the proposed suppositions also can be reliably used for prediction of changes in mass and thickness experienced by cast film NIPS process. It was shown that without the implication of some serious assumptions, it is impossible to derive the old supposition from theoretical concepts. It was also found that the interpretation of film thickness reduction in literatures cannot be validated. Using the presented theoretical concept, one can obtain an overview of the decrease and/or increase in thickness and/or weight of final fabricated membrane prior to any experimental investigation. PubDate: 2017-06-22T23:30:37.044209-05: DOI: 10.1002/adv.21854
Authors:Yanyan Wei; Xiaoyue Ma Abstract: Polymer materials containing Diels–Alder (abbreviated DA) groups show good self-healing ability under certain conditions. In this study, the thermal reversible DA bond was introduced into polyurethane by the design of molecular chain to obtain the self-healing properties. The pre-polyurethane (HTK) end-capped with furan rings was synthesized by hexamethylene diisocyanate trimer and furfuryl alcohol firstly. Then, HTK was mixed with bismaleimide (BMI) to synthesize the cross-linked polyurethane HTK-PU. Finally, the properties of the HTK-PU were characterized. It can be observed from DSC that the DA reaction occurred at 76°C and the r-DA reaction occurred at 109.5°C. This cross-linked polyurethane shows a remarkable high hardness (shore D80). When preserved at 80°C for 6 hr, the self-healing efficiency of the HTK-PU was 53.75% known from tensile test, and cracks on it virtually disappeared as observed from polarizing microscope (POM). When preserved at 80°C for 12 hr, the self-healing efficiency was 67.56%. PubDate: 2017-06-19T00:11:00.867634-05: DOI: 10.1002/adv.21857
Authors:Muthu Rajamani Jayasree; Srinivasan Anandakumar, Muthukaruppan Alagar Abstract: The present work aims at the toughening of DGEBA epoxy-cyanate ester hybrid with caprolactam and its subsequent reinforcement with different weight percentages of (1, 3, 5, and 7 wt%) 3-glycidylpropoxytrimethoxysilane functionalized Al-MCM-41 (F-Al-MCM-41) to fabricate F-Al-MCM-41 reinforced caprolactam toughened DGEBA epoxy-cyanate ester polymer nanocomposites. 1H NMR and 13C NMR data confirmed the formation of epoxy cyanate ester. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) results ascertained the curing behaviour of polymer composites. Data from thermal and dielectric studies reveal that 7 wt% F-Al-MCM-41 reinforced caprolactam toughened DGEBA epoxy-cyanate ester exhibits superior thermal stability and dielectric constant than that of a neat composite. The SEM- EDAX analysis investigated the surface morphology of polymer composites. Data obtained from DMA showed that 7 wt% polymer nanocomposite possesses the highest storage modulus among the samples. PubDate: 2017-06-14T23:43:29.292214-05: DOI: 10.1002/adv.21849
Authors:Hemjyoti Kalita; Rashmirekha Kamila, Smita Mohanty, Sanjay Kumar Nayak Abstract: Biobased polymer has taken tremendous attention in recent times. In the present study bio-based polyurethane have been synthesized from the vegetable oil i.e., dehydrated castor oil, 1,4-butanediol and isophorone diisocyanate in presence of a catalyst by solution polymerization method. Then polyurethane nanocomposites were synthesized using different amount of nanoclay (C30B) (1, 3 and 5 wt%). The synthesis of polyurethane and its nanocomposites were confirmed by FTIR and XRD analysis. The mechanical properties such as tensile strength (2.2–4.5 MPa), elongation at break (299%–435%) hardness (46–70) and abrasion resistance (351–201 mg/1,000 cycles) increased with the increase of nanoclay content. The initial thermal degradation temperature found to increase from (220 to 290°C) with the increase of nanoclay content in the nanocomposites. The nanoclay was interacted with the hard segment of the matrix polymer as reflected from the atomic force microscopy studies. Weathering study revealed that nanocomposites have higher weather resistance capacity than pristine polyurethane. It can be concluded that the prepared nanocomposites might be good outdoor topcoat materials. PubDate: 2017-06-11T23:30:38.946649-05: DOI: 10.1002/adv.21853
Authors:Muhammad Zaman; Muhammad Hanif Abstract: The purpose of the study was to design a dosage form with ability to deliver drug immediately, hence providing rapid relief in certain pain ailments. Meloxicam (MLX) was selected as a model drug and buccal films were designed by using the solvent casting technique. A central composite rotatable design (CCRD) was used as a statistical tool to design and optimize the film formulations. No noticeable interaction was found between the drug and polymer when they were subjected to Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) revealed the smooth surface of the film and uniform mixing of drug and polymer. X-ray diffractometry (XRD) was carried out to observe crystalline and amorphous nature of meloxicam. Differential scanning calorimetric (DSC) analysis was used to investigate the thermal behavior of free drug and drug-loaded formulation. The prepared film showed good mechanical property as folding endurance was found to be greater than 100 in all formulations. The cumulative drug release was found to be more than 80% in initial at dissolution time of 5 min, when the prepared films were subjected to dissolution studies in phosphate buffer at pH 6.8. Thus, it can be concluded that the hydrophilic polymer and plasticizer have definite impact on formulation and characteristics of rapidly dissolving buccal films and have the ability to prepare a suitable immediate release buccal film of meloxicam. PubDate: 2017-06-09T23:20:30.78906-05:0 DOI: 10.1002/adv.21841
Authors:Mozhgan Hayasi; Naghi Saadatjoo Abstract: This work describes the removal of three pharmaceuticals, namely ceftriaxone sodium (CFX), diclofenac sodium (DCF) and atenolol (ATN) from water using magnetic poly (styrene-2-acrylamido-2-methyl propanesulfonic acid) (St-AMPS) adsorbent. This adsorbent was characterized by several techniques such as FTIR, TEM, TGA, VSM and DLS. Three kinetic models, pseudo-first-order, pseudo-second-order and intra-particle diffusion models were used to study the adsorption kinetics. The results showed that the adsorption kinetics of pharmaceuticals onto magnetic poly (St-AMPS) adsorbent followed the pseudo-second-order model and were relatively rapid. In addition, it was found that the intra-particle diffusion was not the sole rate-controlling step and the adsorption of pharmaceuticals onto adsorbent occurred via two steps adsorption process. The experimental data were fitted with three isotherm models including Freundlich, Langmuir and Dubinin-Radushkevich (D-R). It was found that the adsorption of pharmaceuticals onto magnetic poly (St-AMPS) nanoparticles was the best described by the Langmuir model. Maximum adsorption capacities of 150.602, 47.824 and 119.904 mg/g were obtained for DCF, ATN and CFX, respectively. Also the obtained free energy from D-R isotherm (6.19, 4.93 and 6.45 kJ/mol for DCF, ATN and CFX respectively) indicated that the adsorption process was a physiosorption. Magnetic poly (St-AMPS) adsorbent could be recycled for removal of CFX, DCF and ATN by alkaline aqueous solution (pH 8). Therefore, this adsorbent can act as a promising adsorbent for water treatment processes. PubDate: 2017-06-08T23:40:35.414366-05: DOI: 10.1002/adv.21852
Authors:Mohammad Ali Tavanaie; Roya Dastjerdi, Nazanin Sepehrian, Alireza Ghasami Abstract: Nano-titanium oxide/nano-zinc oxide/poly(ethylene terephthalate) (nano-TiO2/nano-ZnO/PET) nanocomposite fibers were successfully prepared by a laboratory-scale melt spinning process. The properties of pure and modified PET fibers including tensile (tenacity and elongation at break) and thermal properties, and the dyeability properties of cationic dyes with and without carrier were studied. The modified PET nanocomposite fiber containing 0.15 wt% nano-titanium dioxide and 0.15 wt% nano-zinc oxide showed the best cationic dye adsorption property, excellent washing fastness and good light fastness. Also, a significant effect on the dye adsorption of modified PET fibers was observed at boiling temperature due to the presence of carrier agent. PubDate: 2017-06-08T02:05:36.709023-05: DOI: 10.1002/adv.21848
Authors:Matthew J. Smith; Casparus J. R. Verbeek Abstract: Novatein thermoplastic protein was blended with modified polyethylene (containing either epoxy, carboxylic acid functionalities partially neutralised to produce zinc carboxylate salts, or maleic anhydride functionalities) to alter blend morphology and to manipulate thermal and mechanical properties. Up to 40 pphNovatein polyethylene (PE) was blended with Novatein by extrusion and injection moulding. Using zinc ionomer resulted in optimal properties and was compatible with a finely dispersed morphology at high content; high interfacial tension (σ) and a viscosity ratio (λ) of ~1 was observed. Unmodified blends and those containing epoxy functionalities showed co-continuity at low PE content. Whilst co-continuity appeared to increase impact resistance, other mechanical properties decreased due to lack of phase interaction. Maleic anhydride-grafted-polyethylene blends showed a finely dispersed PE phase, yet was less compatible. Zinc ionomer was deemed to be the most appropriate for modification of mechanical properties in Novatein. PubDate: 2017-06-07T23:25:59.509903-05: DOI: 10.1002/adv.21847
Authors:Fumitoshi Noguchi; Yuanbing Zhou, Kenichiro Kosugi, Yoshimasa Yamamoto, Phan Trung Nghia, Masao Fukuda, Seiichi Kawahara Abstract: Strain-induced crystallization of natural rubber (NR) can greatly influence the mechanical properties of NR blends. In this study, we investigated the effect of strain-induced crystallization on the tear energy (G) of NR/styrene butadiene rubber (SBR) blends with different compositions and cross-link densities. Using a shift factor, we could superimpose G of an SBR blend and an NR/SBR (1/9) blend onto a single master curve. In contrast, G of NR was split into two master curves. Although the master curve of G for the NR/SBR (3:7) blend was split, increasing the cross-link density threefold made it possible to superimpose it onto a single master curve. Strain-induced crystallization of NR in the NR/SBR blend did not occur as a result of decreasing the NR content, increasing the cross-link density, or removing fatty acids. Together, these findings indicate that strain-induced crystallization of NR plays an important role in the mechanical properties of the blend. PubDate: 2017-06-06T05:50:31.011419-05: DOI: 10.1002/adv.21843
Authors:Siang Tandi Gonggo; Bunbun Bundjali, Ketut Hariyawati, I Made Arcana Abstract: The membranes of sulfonated polystyrene, lignosulfonate and nano-silica (SPS-LS-SiO2) that contain different percentages of nano-silica (1%–5% [w/w]) were prepared and characterized for polymer electrolyte membrane fuel cell (PEMFC). Nano-silica is an inorganic compound with a surface area of 200 m2/g, and it has a hygroscopic property so that the presence of nano-silica in membrane can increase properties of membrane. The SPS-LS-SO2 membranes were prepared by casting polymer solution and membranes were characterized by functional groups analysis, water uptake, ion exchange capacity (IEC), proton conductivity, methanol permeability, thermal stability, mechanical properties, and surface morphology. The results show the increase of nano-silica composition in SPS-LS-SiO2 membranes, the IEC, water uptake, proton conductivity increase, but a pore size of membrane decreases. On the other hand, it can maintain the mechanical strength of membranes. The SPS-LS-SiO2 membranes with nano-silica composition of 2%–5% (w/w) have the same properties with Nafion®117, especially in proton conductivity at the same treatment and measurement conditions, and its methanol permeability is about 28%–35% smaller than that of Nafion®117 (2.09 × 10−6 cm2/s), so this SPS-LS-SiO2 membrane could be used as a polymer electrolyte membrane for direct methanol fuel cell (DMFC) application. PubDate: 2017-06-05T04:50:20.04672-05:0 DOI: 10.1002/adv.21844
Authors:Gianluca Cicala; Salvatore Mannino, Alberta Latteri, Giulia Ognibene, Giuseppe Saccullo Abstract: Two different epoxy monomers, based on the diglycidylether of bisphenol A (DGEBA) and triglycidyl-p-aminophenol (TGAP), which are di- and tri-functional, respectively, were mixed in varying proportions and cured with bis(2,6-diethylaniline) (MDEA). Toughened epoxy resins were prepared by adding a coPolyethersulfone (coPES) to the resin mixture. The dynamic mechanical and morphological properties of the cured materials were measured. It was found that the blends based on TGAP presented different viscoelastic and morphological behavior compared to DGEBA-based formulations. Mixing TGAP with DGEBA resulted in increased glass transition temperature and homogeneous phase morphology distribution. PubDate: 2017-06-02T04:26:01.533355-05: DOI: 10.1002/adv.21845
Authors:Zhixiang Cui; Zifeng Zheng, Luyin Lin, Junhui Si, Qianting Wang, Xiangfang Peng, Wenzhe Chen Abstract: The drug-loaded polyvinyl alcohol (PVA)/chitosan (CS) composite nanofibers intended to be used as matrix for transdermal drug delivery were fabricated by electrospinning, and then crosslinked through glulataraldehyde (GA). The morphology, chemical structure, thermal behavior, mechanical properties, hydrophilicity and drug release properties of drug-loaded PVA/CS composite nanofibers before and after crosslinking were characterized. The results showed that the morphology of PVA/CS composite nanofibers was not been destroyed in both crosslinking and in vitro drug release process. The Young's modulus, tensile strength, thermal properties and hydrophobicity of crosslinked PVA/CS composite nanofibers significantly increased in comparison with those of PVA/CS (without crosslinking) due to the formation of crosslinking network structure. In vitro release studies showed that crosslinked PVA/CS composite nanofibers had lower drug release rate and smaller amount of drug burst release than that of PVA/CS. According to release exponent “n”, the release of ampicillin sodium from crosslinked PVA/CS composite nanofibers fit to the Fickian diffusion mechanism. Those results demonstrate the potential utilization of crosslinked PVA/CS composite nanofibers as a transdermal drug delivery system. PubDate: 2017-06-02T01:05:49.115859-05: DOI: 10.1002/adv.21850
Authors:Dan Zhang; Eusebio Cabrera, Yanan Zhao, Ziwei Zhao, Jose M. Castro, Ly J. Lee Abstract: Multifunctional carbon nanofiber (CNF) nanopaper-enhanced glass fiber reinforced epoxy polymer composites (GFRPC) with improved sand erosion resistance, mechanical properties, and electromagnetic interference (EMI) shielding have been fabricated and tested in this work. Preformed CNF thin film or nanopaper, made of dense and entangled nanofiber networks, was molded on the surface of GFRPC as a surface protection layer by vacuum-assisted resin transfer molding. A fivefold improvement in sand erosion resistance in terms of sand erosion rate, and up to 24% improvement in flexural strength were achieved after the incorporation of CNF nanopaper onto thin GFRPC. The CNF nanopaper-enhanced GFRPC showed an EMI shielding of 33–40 dB within a frequency range of 30 MHz to 1.5 GHz. This multifunctional composite material shows good potential for use in wind power industry, commercial electronics housings, and the automotive industry. PubDate: 2017-06-02T00:25:38.50368-05:0 DOI: 10.1002/adv.21846
Authors:Kashif Barkat; Mahmood Ahmad, Muhammad Usman Minhas, Ikrima Khalid, Bushra Nasir Abstract: An oral route of administration is a most acceptable route for a patient, so we designed chemically cross-linked polyethylene glycol-co-poly(methacrylic acid) oral hydrogels (PEGMA 4000) by free radical polymerization method for pH-responsive colon target delivery of oxaliplatin (OXP). Polyethylene glycol (PEG 4000) was cross-linked chemically with methacrylic acid (MAA) in distilled water. Ammonium peroxodisulfate (APS) and N, N-methylene bisacrylamide (MBA) were used as initiator and cross-linker respectively. OXP was loaded in prepared hydrogels. FTIR, DSC, TGA, SEM, and XRD were conducted for characterization of developed hydrogels which endorsed the formation of new polymeric network. The pH-sensitive behavior of hydrogels was observed by swelling dynamics and equilibrium swelling ratio at low (1.2) and higher pH (7.4). Toxicity study was also conducted on rabbits to evaluate toxicity and biocompatibility of developed carrier system to biological system. Hydrogels with higher PEG 4000 concentration showed maximum swelling and higher drug loading at 7.4 pH. Toxicity study confirmed the developed hydrogels as non-toxic and biocompatible for biological system. Resultantly, these hydrogels can become an excellent candidates for colon targeting of OXP to treat colorectal cancer with no toxicity. PubDate: 2017-05-25T01:55:32.710437-05: DOI: 10.1002/adv.21840
Authors:Ren Hao Liu; Wen-Bin Young, Hsu Pe Ming Abstract: This article discusses the application of an in-mold decoration (IMD) technology for the development of three-dimensional molded interconnect devices (3D-MID). The 3D-MID process uses the film printing technology to print the circuit pattern on a plastic film, and then deform it to the shape of the component by thermoforming. Then, the plastic film is placed inside the mold cavity for injection molding, and is attached to the surface of the component after molding. Experiments were performed for the 3D-MID process using a semisphere shape. A simple geometric model was also proposed to correlate the printed film patterns before and after the thermoforming. The geometric model will be used to design the required printing pattern on a 2D film for a given 3D pattern on a component. PubDate: 2017-05-22T06:25:37.76316-05:0 DOI: 10.1002/adv.21830
Authors:Xueyan Liu; Qiurui Liu, Feifan Kong, Xuguang Qiao, Zhixiang Xu Abstract: In this study, a molecularly imprinted polymer (MIP)-fluorescent probe based on hydrophobic CdSe/ZnS quantum dots (CdSe/ZnS@MIP) was designed and synthesized by bulk polymerization for detecting methamidophos (MAP). The CdSe/ZnS@MIP was characterized by Fourier-transform infrared spectroscopy, thermo-gravimetric analysis and adsorption properties, and it exhibited good adsorption capacity and fluorescent stability, and excellent selectivity. Under optimal conditions, the fluorescence showed a good linear decrease in the range of 3.50 × 10−7–0.71 × 10−3 mol/L with a correlation coefficient of 0.995. The limit of detection of the fluorescent probe was 9.16 × 10−8 mol/L, and the relative standard deviation of the method for nine replicate analyses of 4.0 × 10−6 mol/L MAP was 4.1%. Apple and pear samples spiked with MAP at three levels were extracted and determined by the presented method with good recoveries (89.7%–94.9%). The accuracy of the method was verified by gas chromatography for the detection of kidney beans, leek and cucumber samples, and no significant difference was observed for the results of two methods. PubDate: 2017-05-22T02:00:32.702102-05: DOI: 10.1002/adv.21838
Authors:Mehdi Hatami; Nader Djafarzadeh, Hamed Hasanabadi Abstract: In this research, the effects of organic-inorganic hybrid nanocomposites as novel nanostructure additives in paint compositions were studied. The silica modified TiO2 nano structure was prepared by using sol–gel method. The TEM analysis indicated that these particles were in the range 10–15 nm. The organo silicone containing polymer was prepared by free radical polymerization process. The prepared polymer/mixed metal oxides nanocomposites were fabricated and demonstrated as nanostructure additives. The prepared nanocomposite was introduced into the road marking material formulation. In the first part of the current study, the prepared samples were evaluated by quality control experiment such as compatibility and color visualization tests. Also specific experiments such as hydrophobicity, adhesion, exposure to weathering conditions, self-cleaning nature of the samples, gloss appearance, hardness of the prepared samples, anti-pollution investigation, moisture resistance, and heat-cold cycle's tests were evaluated. The environmental issue of the road marking material and also the dirtiness removal efficiency by using nanostructure coating was investigated. The prepared samples showed 4–7 mg weight loss per hundred square centimeters during the exposure to 300 h by 313 nm UVB irradiation. The best photocatalytic performance in road marking application was found for NA 3% sample. PubDate: 2017-05-20T01:40:32.049367-05: DOI: 10.1002/adv.21842
Authors:Shiv Kumar; Katharina Achazi, Kai Licha, Priyanka Manchanda, Rainer Haag, Sunil Kumar Sharma Abstract: Cyanine 3 is an amphiphilic fluorescent dye used in optical imaging, bioengineering, and for cellular internalization. However, the applications of the dye are limited due to its poor aqueous stability, aggregation tendency, and lack of selectivity. To address these issues, we have developed PEG and azidotriglycerol based dendronized polymers using Novozym 435 as a biocatalyst under solvent free conditions. The resulting polymer having azido and hydroxyl functionalities available in the backbone were further grafted with alkyl chains and polyglycerol dendrons using esterification and ‘Click’ chemistry approach. These polymers form stable micelles at micromolar concentration. All the polymers were characterized from their spectral data and their tendency to encapsulate cyanine 3 dye studied using UV-Vis and fluorescence spectroscopy. The cytotoxicity study of the polymers performed against A549 cell lines suggests them to be nontoxic up to a concentration of 500 μg/ml. PubDate: 2017-05-15T01:07:07.683415-05: DOI: 10.1002/adv.21839
Authors:Yuan Lei; Changbing Li, Xiaowei Fu, Jingxin Lei, Changlin Zhou Abstract: The polyamide-6 based poly(ether-block-amide) (PEBA) multiblock copolymers were reactively prepared in typical processing equipment, torque rheometer. The reactive processing conditions of PEBA were discussed in details on the base of the tensile strength as the main quantization parameter and the torque rheological curves. The optimized reaction temperature, reaction time, and rotational speed were 150°C, 10 min, and 40 rpm respectively. The chemical structure, tensile properties, thermal transition, thermal stability, water absorption, and solubility in organic solvents of PEBA prepared in optimized reaction conditions were characterized by Fourier transform infrared spectroscopy, tensile testing, differential scanning calorimetry, thermogravimetric analysis, and soaking testing in water and organic solvents. The tensile strength and elongation at break of PEBA are 35.9 MPa and 580% respectively. The glass transition temperature and melting temperature of soft segment of PEBA are −50 and 15°C, respectively; the glass transition temperature and melting temperature of hard segment of PEBA are 50 and 140°C respectively. Meanwhile, the PEBA has low water absorption, robust organic solvent resistance, and good thermal stability. The optimization process of PEBA will give the deep understanding of reactive processing of polymer materials. PubDate: 2017-05-08T01:05:04.035672-05: DOI: 10.1002/adv.21837
Authors:Emre Baştürk; Emrah Çakmakçi, Seyfullah Madakbaş, Memet Vezir Kahraman Abstract: Proton-conductive electrospun nanofibers are promising potential materials for several advanced technological applications such batteries, sensors, and fuel cells. In this work, we prepared poly(vinyl butyral)/polyaniline (PVB/PANI) nanofibers via electrospinning and determined their proton conductivities. Structural characterization of the nanofibers was performed by FTIR analysis. Surface morphology of the nanofibers was determined by SEM and AFM. The addition of PANI significantly affected the fiber morphology, and over 90% reduction (with respect to neat PVB nanofibers) in the average nanofiber diameters was observed. Nanofiber mats were doped with polyphosphoric acid. The proton conductivity of the 2 wt.% PANI containing blend nanofibers was found as 18 × 10−6 S/cm at room temperature and at 100% humidity. PubDate: 2017-05-08T00:33:55.851469-05: DOI: 10.1002/adv.21836
Authors:Prabina Kumar Patnaik; Sandhyarani Biswas Abstract: This article reports on mechanical and slurry abrasion response of a new class of material developed by reinforcement of blast furnace slag (BFS) in needle-punched nonwoven polyester fabric epoxy composites. These epoxy-based composites are prepared by the hand-lay-up technique with the variation of BFS content (0, 5, 10, and 15 wt. %) and at constant fiber loading. It is observed that the mechanical properties of the composites are improved significantly with the incorporation of filler. However, the properties like tensile, flexural and inter-laminar shear strength are reduced beyond 10 wt. % of filler loading. Abrasive wear behavior of these composites is studied in the slurry environment by a slurry abrasion test rig (ASTM G105). The specific wear rate of composites under a steady-state condition with respect to normal load and sliding velocity is found to decrease with the increase in filler loading. Further, experimental design through Taguchi's L16 orthogonal array is applied to determine the optimal parametric combination which reduces the wear rate. The parametric combination among sliding velocity of 0.93 m/s, normal load of 30 N, sliding distance of 600 m, silica sand size of 100 μm and filler loading of 5 wt. %, produces an optimum specific wear rate. The morphological study is conducted on abraded composite surfaces by using scanning electron microscopy (SEM) and possible wear mechanisms responsible for wear have been discussed. PubDate: 2017-05-02T10:49:51.264891-05: DOI: 10.1002/adv.21835
Authors:Hideyuki Uematsu; Yu Suzuki, Yoshiyuki Iemoto, Shuichi Tanoue Abstract: Composites of polypropylene (PP) and PP blended with maleic anhydride-grafted polypropylene (MAPP) reinforced with short glass fibers were prepared via extrusion compounding and injection molding techniques. The fiber length did not significantly change irrespective of the presence of MAPP after compounding and injection molding. However, the tensile strength of PP/fiber showed significant improvement after MAPP addition. The interfacial shear strength between PP and fiber increased with the addition of MAPP. Examination of the failure surface of a dumbbell specimen after tensile testing confirmed that the fiber highly orientated in the flow direction in the PP/MAPP matrix. The tensile strength enhancement was attributed to the improvement of the interfacial shear strength between PP and fiber. Moreover, in the injection molding process, there was high orientation of the fiber in the flow direction when there was MAPP. We concluded that the presence of MAPP causes increased orientation of the fiber. PubDate: 2017-04-27T11:12:28.713727-05: DOI: 10.1002/adv.21834
Authors:Na Liang; Yufei Tu, Jing Xu, Dongzhi Chen, Hongwei Zhang Abstract: A novel strategy for fabricating nanocomposite anion exchange membranes (AEM), which can construct self-assembled ionic channels via in situ Menshutkin reaction, is proposed. The TEM image of a nanocomposite AEM based on chloromethylated polysulfone (CMPSF) and functionalized polyhedral oligomeric silsesquioxane (POSS) confirms the existence of core-shell clusters. The ionic conductivity of these nanocomposite AEMs shows a notable increase when the content of functionalized POSS exceeds the percolation threshold. Furthermore, the optimized nanocomposite AEM has higher ionic conductivity than the control AEM with similar ion-exchange capacity due to the well-developed morphology. PubDate: 2017-04-24T04:45:30.818681-05: DOI: 10.1002/adv.21831
Authors:Andrea Dorigato; Marco Brugnara, Alessandro Pegoretti Abstract: In this study, novel electrically conductive polymeric nanocomposites based on polybutylene terephthalate (PBT) filled with commercial carbon black (CB) and carbon nanotubes (CNTs) at different relative ratios have been investigated. Field emission scanning electron microscope (FESEM) analysis revealed how a good nanofiller dispersion was obtained both by introducing CB and CNT. Melt flow index measurements highlighted that the processability of the nanocomposites was heavily compromised at elevated filler amounts, and the viscosity percolation threshold was established at 3 wt% for CNTs and between 6 and 10 wt% for CB nanocomposites. Differential scanning calorimetry (DSC) measurements evidenced how the presence of CNT slightly increased the glass transition temperature of the materials, and an increase of 12°C of the crystallization temperature was obtained with a CNT amount of 6 wt%. Also the crystalline fraction was increased upon CNT addition. Electrical resistivity measurements evidenced that the most interesting results were obtained for nanocomposites with a total filler content of 6 wt% and a CNT/CB relative amount equal to 2:1. The synergistic effect obtained with the combination of both nanofillers allowed the achievement of a rapid surface heating through Joule effect even at applied voltages of 2 V. PubDate: 2017-04-21T23:36:28.295175-05: DOI: 10.1002/adv.21833
Authors:Richard Eungkee Lee; Atefe Afsari Ghazi, Taher Azdast, Rezgar Hasanzadeh, Sajjad Mamaghani Shishavan Abstract: In this study, the tensile strength and M-Rockwell hardness of polycarbonate (PC)-nanoalumina composites are investigated under various processing parameters. For this purpose, PC using a twin-screw extruder is melt compounded with nanoparticle of Al2O3 in the presence of styrene-co-maleic anhydride (SMA) as the compatibilizer. Influences of weight percentage of nanoalumina and injection processing parameters including injection pressure and holding pressure (all in four levels) are investigated on tensile and hardness properties of nanocomposite samples using Taguchi's L16 orthogonal array. The scanning electron microscopy (SEM) results reveal that an appropriate distribution of nanoparticles in polymeric matrix is achieved. According to the results, nanoalumina content is the most effective parameter on tensile strength and hardness with about 51% and 85% contribution, respectively. Results indicate that by addition 1.5 wt% of nanoalumina, the tensile strength and hardness of samples increase as much as 4.5% and 11%, respectively. Also, the results reveal that injection pressure and holding pressure are also effective parameters to change hardness and tensile strength. PubDate: 2017-04-17T02:15:50.886738-05: DOI: 10.1002/adv.21832
Authors:Chin Wei Lai; Foo Wah Low, Mun Foong Tai, Sharifah Bee Abdul Hamid Abstract: In the present study, oleic acid (OA)-decorated magnetite nanoparticles (MNPs) were synthesized via in situ co-precipitation method using ammonium hydroxide as a precipitating agent. This study aims to determine the optimum loading amount of OA for improving the MNPs colloidal stability. Based on our results obtained, it was found that the zeta potential values of MNPs increased from −29.8 to −58.1 mV after modification of MNPs with 1.2 wt.% of OA. Indeed, results obtained clearly to show that a maximum colloidal stability of MNPs in a basic medium could be significantly improved. As a result, this resultant colloidal suspension performance was approximately 7 times higher (21 days- high colloidal stability against precipitation and agglomeration) than that of the undecorated MNPs sample (3 days). Based on vibrating sample magnetometer (VSM) analysis, the resultant OA-decorated MNPs exhibited superparamagnetic behavior with slightly lower saturation magnetization (51–69 emu/g) than that of undecorated MNPs sample (80 emu/g) at room temperature. This behavior was attributed to the sufficient carboxylate ions from the outer layer of the bilayer of OA-decorated MNPs, which promoted the high colloidal stability performance. PubDate: 2017-04-11T04:20:43.810624-05: DOI: 10.1002/adv.21829
Authors:Ali Olad; Hamed Gharekhani, Abdolreza Mirmohseni, Ahmad Bybordi Abstract: A novel fertilizer-integrated superabsorbent nanocomposite based on maize bran (MB), acrylic acid (AA), and acrylamide (AAm) was synthesized in an aqueous solution containing montmorillonite (MMT) and NPK fertilizer compound. FTIR spectra indicated that hydroxyl group of the starch molecules in MB composition has participated in grafting reaction with acrylate-based monomers. The swelling behavior of the synthesized hydrogels in different salt and pH solutions was evaluated. Also, the N,N′-methylenebisacrylamide (MBA) and MMT contents were systematically optimized to obtain a highest swelling capacity. Fertilizer release assessments on the NPK-loaded superabsorbent nanocomposite confirmed the effective role of MMT nanolayers in slow-release property of the prepared formulation. Also, the prepared fertilizer formulation exhibited good water retention capacity in soil. As a result, this eco-friendly and economical product can effectively reduce fertilizer loss, improve water utilization efficiency, and prolong irrigation cycles which are benefit for agricultural applications, especially in drought-prone environments. PubDate: 2017-04-06T02:04:23.425843-05: DOI: 10.1002/adv.21825
Authors:Kulmani Mehar; Subrata Kumar Panda Abstract: The deflection behavior of carbon nanotube-reinforced composite plate is investigated numerically using the finite-element method and the result accuracy is established via three-point experimental bending test data. The physical composite panel model is realized with the help of new mathematical model based on the higher order kinematic theory and the responses are computed using the in-house computer code in the MATLAB environment. Further, the efficacy of the current higher order finite-element model has been established by comparing the deflection responses with those of the references, simulation values (ANSYS), and the in-house experimentation including the experimental elastic properties. Finally, the effect of different design parameters, such as aspect ratio, thickness ratio, edge constraints including the types of load on the deflection and stress responses of the composite plate has been studied in detail. PubDate: 2017-04-04T00:35:30.963637-05: DOI: 10.1002/adv.21821
Authors:Raj K. Singh; Aruna Kukrety, Arvind Kumar, Ajay Chouhan, Rakesh C. Saxena, Siddharth S. Ray, Suman L. Jain Abstract: Three copolymeric and two homopolymeric additives were synthesized utilizing the C18 alkyl acrylate (C18Ac) and N,N-dimethylacrylamide (DMAA) monomers. Three additives named as additive 1, additive 2, and additive 3 were synthesized by varying the ratio between C18Ac: DMAA as 1:1, 1:2 and 2:1 respectively by free radical polymerization using AIBN (azobis(isobutyronitrile)) as initiator, whereas additive 4 and additive 5 were the homopolymers of C18Ac and DMAA, respectively. All the synthesized polymers were characterized by FT-IR (fourier transform infrared spectroscopy), NMR (nuclear magnetic resonance), and GPC (gel permeation chromatography) analysis. Performance evaluation of the copolymers as viscosity index improver (VII), pour point depressant (PPD), antiwear, antifriction, and anticorrosion additives in polyol base oil was done by standard methods. As far as the VII, anti-wear, antifriction, and anticorrosive properties are concerned, additive 2 revealed best performance; however, none of the above synthesized additives was found to be suitable for PPD activity. PubDate: 2017-04-03T00:15:25.920243-05: DOI: 10.1002/adv.21826
Authors:Ling Weng; Peihai Ju, Xiaorui Zhang, Lizhu Liu Abstract: With the rapid development of the electronics industry, dielectric materials with a high-dielectric constant are playing an increasingly important role in the performance of electronic devices. In this study, a composite that employed polyvinylidene fluoride (PVDF) as a matrix and four-needle zinc oxide whisker (T-ZnOw) for reinforcement was prepared by casting method. The microstructure and crystallization behavior of the PVDF/T-ZnOw were analyzed by SEM, FT-IR and XRD. Thermal stability and electrical properties of the composites, included the dielectric constant, dielectric loss and electrical breakdown strength, were tested. Analysis on microstructures indicated that the T-ZnOw in composites were uniformly dispersed and some of the whisker's tips had penetrated through the surface of the composites because of the special four-needle structure. Experimental results showed that the addition of T-ZnOw significantly improved the thermal stability of the composites. Broadband dielectric spectroscopy test results showed that the dielectric properties and conductivity of the composites significantly improved with the increase in T-ZnOw contents. The dielectric constant of the composites was 113 at 100 Hz when the T-ZnOw content was 20% at weight content. PubDate: 2017-04-02T23:10:55.496895-05: DOI: 10.1002/adv.21822
Authors:Sema Vural; Turgay Seckin Abstract: In this study, polystyrene- and poly(methyl methacrylate)-grafted polyimide films were prepared successfully using click chemistry and the ATRP technique. Firstly, kapton films were prepared from stepwise thermal imidization of polyamic acid. Surface modification of kapton films was then achieved by chloromethylation followed by the azide decoration process. For surface grafting of kapton films, polystyrene and poly(methyl methacrylate) as alkyne functional polymers were prepared with alkyne and bromine double functionality using propargyl-2-bromopropionate as an initiator. A coupling reaction with azide-decorated PI surface and alkyne functional polymers was achieved via the Huisgen-1,3-dipolar cycloaddition reaction. FTIR spectroscopy, contact angle measurement, thermogravimetry (TG) and differential scanning calorimetry (DSC), energy dispersive X-ray analysis (EDX) and GPC techniques were used to characterize the grafted polyimides. According to the TG analysis, kapton film was modified at the rate of 8% and 10% with PS and PMMA, respectively. PubDate: 2017-03-31T06:35:36.98267-05:0 DOI: 10.1002/adv.21827
Authors:Yao Xiao; Lixia Bao, Xiaowei Fu, Bo Wu, Weibo Kong, Changlin Zhou, Jingxin Lei Abstract: Effect of phase separation on the water resistance of green waterborne polyurethanes was discussed for the first time. Phase separation was studied through the application of dynamic mechanical analysis. Water resistance was characterized by water absorption ratio and water contact angle. The results showed that the phase separation had stronger effect on water resistance compared with the content of hydrophilic segments of green waterborne polyurethanes; higher phase separation degree led to better water resistance even though the content of hydrophilic segments increased. And, fluorescence microscope images of fluorescent dye inside the green waterborne polyurethane films justified this viewpoint. PubDate: 2017-03-27T00:05:33.110582-05: DOI: 10.1002/adv.21818
Authors:Yuzeng Li; Qiao Li, Gesheng Yang, Ruihao Ming, Minmin Yu, Huihui Zhang, Huili Shao Abstract: Poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) with various molecular weights (MW) were melt blended in equivalent proportions, and then followed by injection molding to form polylactide stereocomplex (sc-PLA). The crystalline structures, thermal resistance, and mechanical properties of the formed sc-PLA were then investigated in detail. The results showed stereocomplex crystallites (sc) were formed predominantly in all the sc-PLA regardless of the MW of the PLLA or PDLA pellets, and a small amount of homocrystallites (hc) also coexisted in sc-PLA. The MW of PLLA and PDLA pellets displayed significant effects on the crystallinity, thermal resistance, and mechanical properties of sc-PLA. PLLA and PDLA with low and similar MW facilitated the formation of sc, and also improved the onset degradation temperature and Vicat softening temperature of sc-PLA. For a similar degree of crystallinity, high MW was found to be more favorable in improving the thermal performance of sc-PLA. Although sc-PLA prepared from PLLA and PDLA with low MW showed decreased mechanical properties, the mechanical properties of sc-PLA increased with an increase in the MW of the PLLA or PDLA pellet. When PLLA and PDLA pellets with high and similar MW were used, the mechanical properties of sc-PLA could even exceed those of pure PLLA. PubDate: 2017-03-25T01:20:28.841665-05: DOI: 10.1002/adv.21824
Authors:Konrad Terpiłowski; Agnieszka Ewa Wiącek, Małgorzata Jurak Abstract: Wettability properties of polyetheretherketone (PEEK) activated and non-activated by nitrogen plasma have been investigated. Moreover, the PEEK plates were covered with antibacterial chitosan and its wettability properties were also investigated. Surface topography was determined using SEM and optical profilometry and surface composition by FT-IR and XPS. For determination of apparent surface free energy, the hysteresis approach (CAH), acid base (LWAB), and Owens–Wendt (O–W) theory were used. The equilibrium contact angles were calculated from the Tadmor theory and further used for apparent surface energy calculation applying the above-mentioned approaches. Due to the surface plasma activation both the roughness of the surface and the polar component of apparent surface free energy increased. It is shown that nitrogen plasma activation of PEEK surface increases the adhesion of chitosan to the surface due to the combination effect of: (i) the increase in surface roughness, (ii) introducing the polar groups onto the surface. PubDate: 2017-03-25T01:15:49.690434-05: DOI: 10.1002/adv.21813
Authors:Majid Naghibzadeh; Mohsen Adabi, Hamid Reza Rahmani, Mohsen Mirali, Mahdi Adabi Abstract: In this research, the polyvinyl alcohol (PVA) nanofibers through forcespinning process were successfully produced and the effective parameters for predicting nanofibers diameter using artificial neural network (ANN) were investigated. The various parameters of forcespinning process including rotational speed, orifice, distance to the collector, and polymer concentration were designed to produce PVA nanofibers. Scanning electron microscopy (SEM) showed that the produced fibers diameter was in the range of 0.56–1.9 μm. The neural network with four input factors, three hidden layers with 5, 10, 1 nodes in each layers, respectively, and one output layer had the best performance in the testing sets. Moreover, the mean squared error (MSE) and linear regression (R) between observed and predicted nanofibers diameter were about 0.1077 and 0.9387, respectively, demonstrating a suitable performance for the prediction of nanofibers diameter using the selected neural network model. PubDate: 2017-03-23T01:40:31.808248-05: DOI: 10.1002/adv.21817
Authors:Zong-Keng Kuo; Mei-Yen Fang, Tu-Yi Wu, Ted Yang, Hsiang-Wen Tseng, Chih-Chen Chen, Chao-Min Cheng Abstract: Hydrophilic materials have been used in many fields, but have recently garnered growing attention in biomedicine. To promote the development and use of suitable hydrophilic materials for biomedical applications, we used three hydrophilic films of varying hydrophilicity and examined the effects of their hydrophilicity on blood compatibility, protein adsorption, blood clotting time, hemolytic activity, biocompatibility, and cell attachment. Across the spectrum of hydrophilicity examined, no obvious differences in biocompatibility were observed. While high material hydrophilicity was associated with higher hemolytic activity, it still fit the nonhemolytic criteria. Further, higher hydrophilicity decreased protein adsorption and cell attachment, but increased thromboresistance in our blood clotting time assay (~30% higher blood clotting index at 10 min). These results indicate that hydrophilicity increases blood compatibility with regard to thromboresistance, but reduces cellular compatibility (i.e., cell attachment), characteristics that could be exploited for a wide range of potential applications in various fields, such as glucose electrode test strips. PubDate: 2017-03-23T01:30:43.613949-05: DOI: 10.1002/adv.21820
Authors:Muhammad R. Islam; Nadia Isa, Ahmad N. Yahaya, Mohammad Dalour Hossen Beg, Rosli M. Yunus Abstract: Three different processing techniques, extrusion, injection, and compression, were followed to fabricate poly (lactic acid) (PLA) and Moringa oleifera fiber (MOF) based composites. Chopped fibers of length 3–5 mm were used for the extrusion followed by injection molding, whereas long-length fibers (~100 mm) were used for compression molding process. For compression molding, long-length fibers were spread in single and double layers. The interfacial shear strength of the composites was evaluated by fiber pull-out testing. Composites were characterized for fracture behavior and mechanical properties. Additionally, surface morphology was also observed by scanning electron microscopy, whereas crystalline properties were evaluated by X-ray diffraction analysis. Analyses revealed that compression molding with double layers of long-length fibers reinforcement showed better properties than other samples. Tensile strengths of extruded and compression processed samples (double-layered) were 75.5 and 81.1 MPa, which are approximately 33% and 44% higher respectively than neat PLA (56.5 MPa). The crack generation of PLA during applied load was observed and found eliminated for the double-layered sample processed via compression molding. It was found that compression molding with double layer can be considered as easy and less time-consuming method for composite preparation, with nearly 8 wt.% of less fiber consumption compared with extrusion/injection molding. PubDate: 2017-03-23T01:30:37.257271-05: DOI: 10.1002/adv.21823
Authors:Zhongbo Song; Weijun Zhen Abstract: Poly(D-lactic acid) (PDLA) was prepared from D-lactic acid under optimized polymerization conditions of 1 wt% stannous octoate, at 170°C for 12 hr. Poly(L-lactic acid) (PLLA) and its optical isomer, PDLA, were blended to improve the thermal and mechanical properties. Mechanical testing showed an increase in the impact strength of the PLLA/PDLA (0.3 wt%) by 27.6%. SEM showed more shear zones and fibrillation on the composite surfaces, compared withthe PLLA, suggesting high toughness and shock strength. TGA showed the enhanced thermal stability of PLLA composites. The DSC results indicated that the crystallinity of PLLA/PDLA (0.3 wt%) was increased by 54.31%, compared with pure PLLA. Non-isothermal crystallization kinetics suggested the formation of crystal nucleus and the growth rate of PLLA/PDLA (0.3 wt%) increased gradually. Half crystallization time showed a decreasing trend, which could provide a large number of heterogeneous nucleation sites and improved the crystallization rate of PLLA. PubDate: 2017-03-23T01:20:46.477106-05: DOI: 10.1002/adv.21816
Authors:Łukasz Piszczyk; Paulina Kosmela, Michał Strankowski Abstract: Elastic polyurethane foams were produced from two-component polyurethane systems (SPECFLEX NE 113 izocyjanian/NR 816 poliol system—SPC and Elastic MBMarket company system POLYOL ET MB 500/ISO ET MB 800—ET) by using a one-step method. The foams were a graphene nanoplatelets (GNP) in the amount ranging from 1 to 2 wt.%. The effect of the nanofiller on polyurethane matrix was determined by analyzing the chemical structure, static and dynamic mechanical properties, and thermal stability of reinforced foams. The application of the carbon nanofiller resulted in increased density and hardness of the obtained composites. The addition of the nanofiller caused a shift in glass transition temperature toward lower temperature values, and an increase in the Young's modulus, but did not significantly affected the thermal stability of the obtained composites. The research results showed that graphene nanoplatelets nanofiller can be successfully used as a modifier of mechanical and thermal properties in elastic polyurethane foams. PubDate: 2017-03-20T23:51:26.108714-05: DOI: 10.1002/adv.21819
Authors:Jingyao Sun; Daming Wu, Ying Liu, Le Dai, Chong Jiang Abstract: Filling process of micro prism array by isothermal hot embossing in solid-like state (IHESS) with different mold temperature, pressure, and holding time were simulated by DEFORM. Polymethyl methacrylate (PMMA) samples processing by IHESS were tested to validate the numerical simulation results and select the best processing condition. The reliability of simulation was tested quantitatively and qualitatively by comparing the cross-profile and its developing trend separately. It was found that the cross-profiles from the simulations and experiments were in high agreement. The simulated and experimental developing trends of cross-profiles were also the same. These results proved the reliability of simulation and its guidance to the experiments. In order to show the advantages of IHESS, a brief introduction and comparison of IHESS and traditional hot embossing were made. PubDate: 2017-03-20T03:25:38.089871-05: DOI: 10.1002/adv.21815
Authors:Pablo R. Cortez Tornello; Gabriela E. Feresin, Alejandro Tapia, Monika Dzieciuch, Teresita R. Cuadrado, Gustavo A. Abraham Abstract: Poly(ε-caprolactone) microparticles containing embelin (PCLE) are prepared by electrohydrodynamic atomization (EHDA) and emulsion-solvent evaporation techniques. Microparticles are characterized in terms of drug state, drug-loading capacity, encapsulation efficiency, morphology and in vitro release in different mediums. Physicochemical, morphological, and thermal characterization is presented. Kinetic analysis is performed. EHDA microparticles present higher size, surface area, and encapsulation efficiency. The release profiles combine a high initial release, followed by a slow-controlled release stage. Electrosprayed PCLE presented characteristics such as size (3.14 ± 0.05 μm), zeta potential (−49.22 ± 2.88 mV) and release profiles that could be attractive for the development of microcarriers for pulmonary administration of embelin. PubDate: 2017-03-16T23:51:04.51552-05:0 DOI: 10.1002/adv.21814
Authors:Roozbeh Hajiraissi; Yousef Jahani Abstract: It is well-established that rheology can trace structural dynamics and conjectures the forming/formed morphology. The objective of this work is to trace the droplet deformation via conducting fiber spinning process. In this regard, two types of polymer blends Polypropylene (PP)/Polyamide6 (PA6) and Polypropylene/Polytrimethylene terephthalate (PTT) with various ratios (99/1, 94/6, 90/10, and 80/20) were melt-blended on co-rotating twin screw extruder and thereafter, were spun. Scanning electron microscopy (SEM) images represent a droplet and fibrillar morphologies for as-extruded samples and spun blend fibers respectively. Unlike PA6 as dispersed phase, PTT droplets in PP/PTT blend system shows improved spinnability. Linear melt viscoelastic data were gathered by performing rheological approaches in linear region. Conducting frequency sweep at 240°C is revealed a terminal behavior for Gʹ and a Newtonian plateau for η* at low frequencies. However, at 195°C dynamic rheological data pertinent to fibers represent a non-terminal trend for Gʹ and viscosity upturn at low frequencies respectively. These distinguishable characteristics can be considered as spinnability of droplets which reflect fibrillation mechanism, and fibrillar growth can be followed by scanning the viscoelastic responses at low frequency region which enhanced upon fibril growth. According to SEM and rheological test results, PTT, as an engineering plastics, manifests higher capability of forming nano fibrils. PubDate: 2017-02-28T00:45:38.895212-05: DOI: 10.1002/adv.21810
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