bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of cardanol‐based epoxidized novolac resins modified with carboxyl‐terminated butadiene–acrylonitrile copolymer
Authors: Yadav Ranjana , Srivastava Deepak 
Published: June 2009

AbstractCardanol‐based, novolac‐type phenolic resins were synthesized with a cardanol‐to‐formaldehyde molar ratio of 1 : 0.7 with different dicarboxylic acid catalysts, including oxalic and succinic acids. These novolac resins were epoxidized with a molar excess of epichlorohydrin at 120°C in a basic medium. The epoxidized novolac resins were separately blended with different weight ratios of carboxyl‐terminated butadiene–acrylonitrile copolymer (CTBN) ranging between 0 and 20 wt % with an interval of 5 wt %. All of the blends were cured at 120°C with a stoichiometric amount of polyamine. The formation of various products during the synthesis of the cardanol‐based novolac resin and epoxidized novolac resin and the blending of the epoxidized novolac resin with CTBN was studied by Fourier transform infrared spectroscopy analysis. Furthermore, the products were also confirmed by proton nuclear magnetic resonance and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy analysis. The molecular weights of the prepared novolacs and their epoxidized novolac resins were determined by gel permeation chromatography analysis. The blend samples, in both cases, with 15 wt % CTBN concentrations showed the minimum cure times. These blend samples were also the most thermally stable systems. The blend morphology, studied by scanning electron microscopy analysis, was, finally, correlated with the structural and property changes in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The effect of CTBN concentrations on the kinetic parameters of decomposition of blends of cardanol‐based epoxidized novolac resin modified with carboxyl‐terminated liquid copolymer
Authors: Yadav Ranjana , Srivastava Deepak 
Published: June 2009

AbstractCardanol‐based novolac resins were separately prepared with different mole ratios of cardanol‐to‐formaldehyde with different acid catalysts. These resins were epoxidized with epichlorohydrin, in basic medium, at 120°C. The resins were, separately, blended with different weight percentages of carboxyl‐terminated butadiene acrylonotrile copolymer and cured with polyamine. Structural changes during blending were studied by FTIR spectroscopic analysis. Coats–Redfern equation was utilized to calculate the kinetic parameters, viz., order of decomposition reaction (n), activation energy (E), pre‐exponential factor (Z), and rate decomposition constant (k), for the decomposition of the samples. It was found that the degradation of the epoxies and their blend samples proceeded in two steps. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Microstructure and rheologic development of polypropylene/nano‐CaCO3 composites along twin‐screw extruder
Authors: Jiang Guo , Huang Han‐Xiong 
Published: June 2009

AbstractPolypropylene/nano‐calcium carbonate (PP/nano‐CaCO3) composites were prepared by using an intermeshing, co‐rotating twin‐screw extruder. Two different screw configurations, denoted by screws A and B, respectively, were employed. The former provided high dispersive mixing and the later provided high dispersive and distributive mixing. Effect of mixing type on microstructure and rheologic development of nanocomposites was investigated by taking samples from four locations along screws A and B. Transmission electron microscopy results show that in the sample at the exit of extruder, the percentage of nano‐CaCO3 particles with the equivalent diameter lower than 100 nm along screws A and B is 66.5 and 79.0%. respectively. Moreover, for screw B, the number‐averaged diameter at four sampling locations is smaller than that for screw A. This means that the distributive mixing, provided by screw B, favors the size decrease of nano‐CaCO3 in the PP matrix. In addition, rheologic results show that the decrease of complex viscosity for the nanocomposites is deeply related to turbine mixing elements, which provides distributive mixing. The online melt shear viscosity of the nanocomposite at the exit of extruder prepared by screw B is lower than that of pure PP. This is related to the dispersion of nano‐CaCO3 in PP matrix. Finally, the relationship between rheologic properties and microstructure was analyzed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of clay contents on the dynamic mechanical and rheological properties of polypropylene/MAH‐g‐POE/clay composites
Authors: Qiao Xiuying , Zhong Weixia , Sun Kang , Chen Xiaodong 
Published: June 2009

AbstractA series of polypropylene/maleic anhydride grafted polypropylene octane elastomer (MAH‐g‐POE)/clay (PPMC) nanocomposites were prepared with a novel compatilizer MAH‐g‐POE and different contents of octadecyl amine modified montmorillonite, and the effects of clay contents on the dynamic mechanical and rheological properties of these PPMC composites were investigated. With clay content increasing, the characteristic X‐ray diffraction peak changed from one to two with intensity decreasing, indicating the decreasing concentration of the intercalated clay layers. The gradual decrease of crystallization temperature of PPMC composites with the increase of clay loading should be attributed to the preferred intercalation of MAH‐g‐POE molecules into clay interlayer during blending, which is also reflected by scanning electron microscopy observations. By evaluating the activation energy for the glass transition process of MAH‐g‐POE and polypropylene (PP) in the PPMC composites, it is found that clay intercalation could cause the restriction effect on the glass transition of both MAH‐g‐POE and PP, and this restriction effect appears stronger for PP and attained the highest degree at 5 wt % clay loading. The melt elasticity of PP could be improved apparently by the addition of MAH‐g‐POE, and 5 wt % clay loading is enough for further enhancing the elastic proportion of PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Enhanced permittivity by the adhesion of conducting and low‐loss insulating ceramics in polystyrene
Authors: George Sumesh , Sebastian Mailadil Thomas 
Published: June 2009

AbstractCa[(Li1/3Nb2/3)0.8Ti0.2]O3−δ (CLNT)–polystyrene–La0.5Sr0.5CoO3−δ (LSCO) three‐phase composites were prepared by a two‐step mixing and hot‐molding method. The dielectric properties of polystyrene–CLNT composites were in agreement with the theoretical predictions. The dielectric properties of the three‐phase composites were investigated in terms of the volume fraction of LSCO and the frequency. The relative permittivity of the composites increased with LSCO loading. These composites with low processing temperatures showed a maximum relative permittivity of the order of 104. These composites, with a giant permittivity with a broad smearing region, can find application in electrostrictive, decoupling capacitors and embedded passive devices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of a novel silicon‐containing polytriazole resin
Authors: Huang Jianxiang , Wan Liqiang , Zhang Jian , Gao Fei , Tian Jianjun , Huang Farong , Du Lei 
Published: June 2009

Abstract4,4′‐Diazidomethylbiphenyl (DAMBP) and poly(dimethylsilylene‐ethynylenephenyleneethynylene) (PDMSEPE) were thermally polymerized to form a novel silicon‐containing polytriazole resin (PDMSEPE‐DAMBP) by 1,3‐dipolar cycloaddition. Differential scanning calorimetry, FTIR, and 13C‐NMR were used to characterize the curing behaviors of PDMSEPE‐DAMBP resins. The results indicated that the resins could cure at temperatures as low as 80°C. Dynamic mechanical analysis showed that there was a glass transition at 302°C for the cured PDMSEPE‐DAMBP resin. The carbon fiber (T700) reinforced PDMSEPE‐DAMBP composites exhibited excellent mechanical properties at room temperature and high property retention at 250°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Comfort, chemical, mechanical, and structural properties of natural and synthetic leathers used for apparel
Authors: Sudha Thomas Balasingh , Thanikaivelan Palanisamy , Aaron Kavati Phebe , Krishnaraj Kaliappa , Chandrasekaran Bangaru 
Published: June 2009

AbstractNatural leather is processed from hides and skins of animals. Synthetic leathers are becoming popular as an alternative material owing to limited availability and varying size of natural leathers. There is a need to understand the properties of natural and synthetic leathers to select proper material for an application. In this study, materials used for apparel application such as natural sheep nappa leather and synthetic polyurethane (PU)‐based leather have been chosen and analyzed for comfort, chemical, physical, and structural properties. It was found that natural sheep nappa leather has enhanced water vapor permeability whereas other comfort properties such as softness and drape ability are comparable to synthetic PU leather. Whereas synthetic PU leather dominated most of the physical properties, especially percentage elongation and stitch tear strength, in specific directions on account of polyester knitted base fabric. Chemical properties of natural sheep nappa leather and synthetic PU leather depended on the individual material composition and characteristics. Scanning electron microscopic (SEM) analysis provided convincing evidence for some of the quantified comfort and physical properties. The results of this study would be useful in selection of proper material for apparel application as well as in providing directions for future research in synthetic leather manufacture. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermoplastic‐modified epoxy resins cured with different functionalities amine mixtures: Morphology, thermal behavior, and mechanical properties
Authors: Blanco Miren , López Marta , De Arcaya Patricia Alvarez , Ramos Jose Angel , Kortaberria Galder , Riccardi Carmen Cristina , Mondragon Iñaki 
Published: June 2009

AbstractEpoxy matrices inherent brittleness and poor crack resistance make necessary some form of toughening. In this work, to improve their fracture toughness and ductility epoxy matrices were modified by changing its architecture and by the addition of a third component. The matrices architecture were modified by stoichiometrically reacting a bifunctional epoxy resin with different functionalities amine mixtures, one of which being a monoamine that plays the role of chain extender. In the modification by the addition of a third component, poly(methyl methacrylate) (PMMA) was selected as modifier. PMMA is initially miscible with epoxy/amine systems but can phase separate during curing. The kinetics and miscibility of these systems were studied previously. At constant curing conditions, materials from completely opaque (phase separated) to transparent (miscible) can be obtained with the increase in monoamine content. In this work, the effects of the modifier content and of the monoamine : diamine ratio in stoichiometric epoxy/amine mixtures on the resultant morphologies as well as on their thermal and mechanical properties was studied.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of the monomer sequential distribution on the mechanical properties and temperature dependence of an ethylene–tetrafluoroethylene copolymer in association with the phase‐transition behavior
Authors: Arai Kiyotaka , Funaki Atsushi , Aida Shigeru , Phongtamrug Suttinun , Tashiro Kohji 
Published: June 2009

AbstractThe temperature dependence of the mechanical properties of a series of ethylene–tetrafluoroethylene copolymers was interpreted reasonably on the basis of experimental information about the crystalline phase transition and the amorphous‐glass transition behaviors. The crystalline phase‐transition temperature, the glass‐transition temperature, and the bulk modulus were found to depend sensitively on the tetrafluoroethylene content. The magnitude of change in the bulk modulus at the crystalline phase‐transition temperature and glass‐transition temperature was also found to depend sensitively on the tetrafluoroethylene content. These experimental data were interpreted from various levels, including the distribution of the sequential ratios of ethylene–ethylene, tetrafluoroethylene–tetrafluoroethylene, and ethylene–tetrafluoroethylene segments in the copolymer chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Comparative studies of polypropylene nonwoven sputtered with ITO and AZO
Authors: Wei Qufu , Shao Dongfeng , Deng Bingyao , Xu Yang 
Published: June 2009

AbstractIn this study, the polypropylene (PP) spunbonded nonwoven materials were used as substrates for depositing transparent nanostructures on the fiber surfaces. Magnetron sputter coating technique was used to deposit tin‐doped indium oxide (ITO) and aluminum‐doped zinc oxide (AZO) films onto the nonwoven substrates. The structures and properties of the deposited ITO and AZO films were investigated and compared using atomic force microscopy, energy‐dispersive X‐ray (EDX), and electrical and optical tests. The observations by atomic force microscopy revealed the formation of functional nanostructures on the fiber surfaces. EDX analyses confirmed the deposition of ITO and AZO functional films on the PP fibers. It was found that ITO had more compact structures on the fiber surface than AZO under the same sputtering conditions. The transmittance analysis revealed that the nonwoven substrates deposited with nanostructural AZO showed better ultraviolet shielding effect than those coated with ITO in the same thickness. The nonwoven materials coated with ITO had lower electrical resistance than those coated with AZO in the same thickness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of a maleic anhydride grafted polypropylene–butadiene copolymer and its application in polypropylene/styrene–butadiene–styrene triblock copolymer/organophilic montmorillonite composites as a compatibilizer
Authors: Cheng Qiaohuan , Lü Zhanxia , Byrne Hugh J. 
Published: June 2009

AbstractA maleic anhydride grafted propylene–butadiene copolymer (MPPB) was prepared. Fourier transform infrared spectroscopy and 1H‐NMR results indicate that the maleic anhydride molecules reacted with the double bond in the butadiene unit of the propylene–butadiene copolymer (PPB), and the grafting percentage increased with the butadiene content in the initial copolymer. The gel permeation chromatography results show that the introduction of butadiene in the copolymer prevented the degradation of PPB. The MPPB was applied in polypropylene (PP)/styrene‐butadiene‐styrene triblock copolymer (SBS)/organophilic montmorillonite (OMMT) composites as a compatibilizer. In the presence of 10‐phr MPPB, the impact strength of the composite was improved by about 20%. X‐ray diffraction patterns indicated the formation of the β‐phase crystallization of PP in the presence of MPPB, and a significant decrease in the spherulite size was observed. Transmission electron microscopy (TEM) images showed that the OMMT was better dispersed in the matrix upon the inclusion of MPPB. A better distribution of the rubber phase and a rugged fracture surface were observed in the scanning electron microscopy images as the MPPB proportion was increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Contribution of the melting stage to the evolution of the morphology and chemical conversion of immiscible polyamide/polyethylene blends in twin‐screw extruders
Authors: Yquel V. , Machado A. V. , Covas J. A. , Flat J. J. 
Published: June 2009

AbstractThis study investigates the effects of processing conditions (the screw speed, throughput, barrel temperature, and screw configuration) on the chemical conversion and morphology evolution of polyamide/polyolefin blends along a twin‐screw extruder. Polymer samples were collected rapidly at specific barrel locations with a special sampling device for subsequent chemical and morphological characterization. Increasing the screw speed or using more restrictive screw modules at the beginning of the melting zone promoted a faster reaction and better dispersion along the extruder. Increasing the throughput or decreasing the barrel temperature slowed the evolution of the morphology and chemical conversion along the extruder because of the lower melting rate. As soon as melting started, the chemical reaction took place. However, high chemical conversion rates required extensive melting, that is, significant interface generation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Characterization of the mechanical and thermal properties and morphological behavior of biodegradable poly(L‐lactide)/poly(ε‐caprolactone) and poly(L‐lactide)/poly(butylene succinate‐co‐L‐lactate) polymeric blends
Authors: Vilay V. , Mariatti M. , Ahmad Zulkifli , Pasomsouk K. , Todo Mitsugu 
Published: June 2009

AbstractTwo series of biodegradable polymer blends were prepared from combinations of poly(L‐lactide) (PLLA) with poly(ϵ‐caprolactone) (PCL) and poly(butylene succinate‐co‐L‐lactate) (PBSL) in proportions of 100/0, 90/10, 80/20, and 70/30 (based on the weight percentage). Their mechanical properties were investigated and related to their morphologies. The thermal properties, Fourier transform infrared spectroscopy, and melt flow index analysis of the binary blends and virgin polymers were then evaluated. The addition of PCL and PBSL to PLLA reduced the tensile strength and Young's modulus, whereas the elongation at break and melt flow index increased. The stress–strain curve showed that the blending of PLLA with ductile PCL and PBSL improved the toughness and increased the thermal stability of the blended polymers. A morphological analysis of the PLLA and the PLLA blends revealed that all the PLLA/PCL and PLLA/PBSL blends were immiscible with the PCL and PBSL phases finely dispersed in the PLLA‐rich phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Moisture and heat transfer in hybrid weft knitted fabric with artificial intelligence
Authors: Yazdi Motahareh Mokhtari , Semnani Dariush , Sheikhzadeh Mohammad 
Published: June 2009

AbstractOne of the most important properties of clothes is their ability to help the body's thermal system to keep the body temperature in its natural range, even if the environmental conditions or physical activities are outside the body's ideal range. Perspiring is one of the most important effects of physical activities in warm weather for shedding the body's excessive heat. Therefore, the basic requirement of a fabric worn next to the skin is to transfer this moisture to the atmosphere to reach comfort through the avoidance of a feeling of wetness and clamminess and also through the generation of a situation for the best surface evaporation of moisture. The main goal of this study was to achieve a kind of fabric that guarantees comfort for the body by good heat and moisture transport. To achieve this goal, a group of double‐surface fabrics containing hydrophilic and hydrophobe fibers were knitted, and their simultaneous heat and moisture transport was evaluated with the help of a perspiration‐simulation machine; the results were analyzed as transfer process plots. Also, the transmission of heat and moisture was evaluated for all of the samples by differential modeling as an artificial neural network. Effective parameters on heat and moisture transfer were taken into consideration with modeling and statistical methods. The results were analyzed to find a suitable fabric with optimum comfort. The final results showed that a fabric made of micropolyester filaments and cotton yarns on the bottom and top surfaces, respectively, had the best heat and moisture transfer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
In situ observation of polypropylene composites reinforced by nonmetals recycled from waste printed circuit boards during tensile testing
Authors: Zheng Yanhong , Shen Zhigang , Cai Chujiang , Ma Shulin , Xing Yushan 
Published: June 2009

AbstractA great amount of work has been done over the past few years to reuse the nonmetals recycled from waste printed circuit boards in polypropylene (PP) composites. This is because of the very fast generation rate of nonmetal pollution in the world each year and the very fast growing rate of PP applications in industries. This work focuses on the dynamic effects of nonmetals of different particle sizes on the tensile properties and reinforcing mechanisms of nonmetal/PP composites by in situ scanning electron microscopy tensile testing. The observed results show that the dominant deformation mechanism in pure PP is shear yielding. When fine nonmetals are filled into PP, mass microcracks are initiated. The glass fibers first resist the cracks and undertake the loading when they propagate. The crazes propagate slowly and then break the glass fibers. When coarse nonmetals are filled into PP, interfacial debonding and mass microcracks are initiated. A crack is either terminated when it meets another fiber–particulate bundle or branched into finer mass crazing. Interfacial debonding, crack initiation and propagation, and fiber pullout and breakage dissipate tremendous energy. These factors cause improvements in the strength and rigidity of nonmetal/PP composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Three‐dimensional flow simulation of resin transfer molding utilizing multilayered fiber preform
Authors: Lee Seung Hwan , Yang Mei , Song Young Seok , Kim Seong Yun , Youn Jae Ryoun 
Published: June 2009

AbstractImpregnation of the multi‐layered fiber preform with injected resin was analyzed by using the control volume finite element method for three‐dimensional mold filling simulation of the resin transfer molding (RTM). Numerically predicted flow fronts were compared with experimental data to validate accuracy of the numerical results and applicability of the numerical code developed in this study. Since isothermal Newtonian flow was assumed, Darcy's law and continuity equation were used as governing equations and permeability tensors employed for each layer. Flow simulation was conducted for the two types of mold geometries, i.e., rectangular plate and hollow cylinder. It was proven by comparing numerical results with experimental data that the simulation code is accurate enough to predict the flow patterns, especially when multi‐layered preforms were placed in the cylindrical mold. It was also found that the filling time was reduced by using outer gates compared with the case of inner gates. Three‐dimensional numerical simulation provided useful information for mold filling and can be used to design an optimum mold and make the RTM process efficient. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of monodisperse styrene/methyl methacrylate/acrylic acid latex using surfactant‐free emulsion copolymerization in air
Authors: Zhang Shengmiao , Chen Jianding , Taha Mohamed 
Published: June 2009

AbstractMonodisperse styrene/methyl methacrylate/acrylic acid (St/MMA/AA) copolymer microspheres have been prepared with surfactant‐free emulsion polymerization in air. The presence of oxygen in the system not only caused an induction period but also decreased the average particle size (Dp). However increasing AA concentration ([AA]) gave a reduction in the induction period. The FTIR and NMR analysis of the latex copolymer confirmed that the correlation of the copolymer compositions with the feed compositions was much better at the lower [AA] than at the higher levels. The AA contents of the copolymers obtained in air were much lower than those of the copolymers obtained under N2 protection. Decreasing [AA] led to decrease in the copolymer molecular weight and broadening of the molecular weight distribution, but the particle size distribution (δ/Dp) was unaffected. In addition, the average particle diameter (Dp) was proportional to [AA]–0.255, and increasing comonomers feed content caused linear increase of Dp, and a monodisperse sample with final solids contents up to 34.2 wt % was obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009