bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screen printable epoxy/BaTiO3 embedded capacitor pastes with high dielectric constant for organic substrate applications
Authors: Jang Kyung‐Woon , Paik Kyung‐Wook 
Published: July 2008

AbstractIn this article, embedded capacitor pastes (ECPs) with various BaTiO3 (BTO) powder contents were formulated and screen‐printed on PCBs to fabricate capacitors. The material properties of the ECPs that included their rheology, curing behavior, and dielectric constant were investigated. Embedded capacitors were fabricated for reliability tests related to the thermal cycling and high temperature and humidity potential of optimized ECPs. Additionally, changes in the dielectric properties were discussed. ECPs were formulated with various powder contents from 0 to 70 vol %. ECP resin was cured at temperatures ranging from 130 to 220°C. All ECPs had the viscosities below 30 Pa · s at a shear rate of 100 s−1 to be easily screen‐printable. The dielectric constant of the cured ECPs increased to 60 at 70 vol %, and the dielectric loss was approximately 0.023 for all ECPs regardless of BTO volume content. For the reliability test, ECPs with 50, 60, and 70 vol % BTO powder contents were selected and embedded capacitors were fabricated. After a thermal cycling test with a temperature range from −55 to 125°C for 1000 cycles, capacitance decreased by approximately 5 ∼ 10%, but the dielectric loss did not change. After a 85°C/85RH% test for 1000 h, the capacitance and dielectric loss increased by nearly 20%. Cyanoresin (CRS) was used to form the high dielectric polymer/ceramic composite material. The newly formulated resin system had a dielectric constant that is double that of a conventional epoxy resin system. Additionally, the dielectric constant of the polymer/ceramic composite material increased 50% at 50 vol %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and properties of cyclo‐olefin copolymer/titania hybrids
Authors: Ou Cheng‐Fang , Hsu Ming‐Chieh 
Published: July 2008

AbstractA series of organic–inorganic hybrid materials consisting of an organic cyclo‐olefin copolymer (COC) and inorganic titania (TiO2) were successfully synthesized by a sol–gel process. TiO2 was obtained through the hydrolysis of titanium n‐butoxide (TNBT) with the catalysis of HCl. Differential scanning calorimetry analysis indicated that the glass‐transition temperature of the hybrids was higher than that of pure COC, and it rose significantly as the TNBT content was increased from 1 to 15 wt %. Scanning electron microscopy observations showed that the morphology of fractured surfaces of the COC/TiO2 hybrid with 5 wt % TNBT was a single homogeneous phase, indicating that the miscibility between COC and TiO2 was good for the hybrids. According to ultraviolet–visible analysis, the transmittance of pure COC at 550 nm was high up to 91.7%. The light transmittance of the COC/TiO2 hybrids was still higher than 80% with the TNBT content up to 5 wt %. The decomposition temperatures of the hybrids, investigated with thermogravimetric analysis, were not affected significantly by the addition of TNBT. The oxygen barrier property of the hybrid films showed significant improvements in comparison with pure COC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of silica‐based nanofillers on the properties of a low‐density polyethylene/ethylene vinyl acetate copolymer based thermoplastic elastomer
Authors: Hui S. , Chaki T. K. , Chattopadhyay S. 
Published: July 2008

AbstractThe effect of pristine silica nanoparticles on a model low‐density polyethylene (LDPE)–ethylene vinyl acetate copolymer (EVA) thermoplastic elastomer blend system is explored in this article. Pristine silica nanoparticles were melt‐blended with the LDPE–EVA system at 1.5, 3, and 5 wt % loadings through the variation of the sequence of addition. In one of the compositions, coupling agent bis[3‐(triethoxysilyl)propyl] tetrasulfide (Si‐69) was used to improve the interaction of hydrophilic silica fillers with the polymer matrix. The blends were compression‐molded, and their mechanical, dynamic mechanical, and thermal properties, X‐ray diffraction patterns, and morphology were evaluated. The properties of the blends were found to be strong functions of the sequence of addition of nanofillers during their preparation. With Si‐69 as a coupling agent, the dynamic storage modulus of nanosilica‐based composites was found to increase up to 35%. An appreciable improvement in the tension set properties of the thermoplastic elastomer nanocomposites was observed in all the nanosilica‐based films. Morphological studies and dynamic properties clearly indicated that the differential properties of these blend systems primarily stemmed from the extent of dispersion and alternation of crystalline morphology, which in turn was a strong function of preferential incorporation in the LDPE or EVA matrix and the agglomeration tendency of the nanofillers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal stabilization effect of biphenol monoacrylate on polyamide 6
Authors: Yang Tao , Ye Lin , Shu Ying 
Published: July 2008

AbstractBiphenol monoacrylate (AL) was combined with a traditional hindered phenolic‐based binary antioxidant system to form a ternary stabilization system for the purpose of further improving the thermal–oxidative stability of polyamide 6 (PA6). The thermal stabilization effect of the antioxidant AL on PA6 was studied in terms of the reduced viscosity, the chemical structure, the yellow index, and the mechanical properties. The results showed that the antioxidant AL, with the proper chemical structure, could improve the thermal stability of PA6 effectively through a unique bifunctional stabilizing mechanism. The interaction of the molecules of PA6 with the antioxidant AL was investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Optomechanical properties of the morphology of viscose fibers due to the cold‐drawing process
Authors: Fouda I. M. , Seisa E. A. 
Published: July 2008

AbstractThis study sheds light on the changes produced by the effects of cold‐drawn fibers on the microstructure and macrostructure of viscose fibers. The optical properties and strain produced in viscose fibers were measured interferometrically at room temperature. Structural parameters were calculated, such as the work per unit of volume, the reduction in entropy due to elongation, and the harmonic mean specific refractivity. In addition, the resulting data were used to calculate the optical stress coefficient and optical configuration and to apply the Mooney–Rivlin equation to determine the constants. Also, the number of crystals per unit of volume and the average orientation angle for uniaxial stretching were calculated with the extension ratios. The relation between the true stress and strain hardening was calculated. The average value of the maximum birefringence was determined to equal 0.046. The relations between the optical and mechanical changes with different parameters were established for the studied fibers. Microinterferograms and curves were drawn for illustration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polyhydroxybutyrate/acrylonitrile‐g‐(ethylene‐co‐ propylene‐co‐diene)‐g‐styrene blends: Their morphology and thermal and mechanical behavior
Authors: de Carvalho Fabiana Pires , Quental Antonio Carlos , Felisberti Maria Isabel 
Published: July 2008

AbstractPolyhydroxybutyrate (PHB) is a biodegradable bacterial polyester emerging as a viable substitute for synthetic, semicrystalline, nonbiodegradable polymers. An elastomer terpolymer of acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene (AES) was blended with PHB in a batch mixer and in a twin‐screw extruder to improve the mechanical properties of PHB. The blends were characterized with differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy, and impact resistance measurements. Despite the narrow processing window of PHB, blends with AES could be prepared via the melting of the mixture without significant degradation of PHB. The blends were immiscible and composed of four phases: poly(ethylene‐co‐propylene‐co‐diene), poly(styrene‐co‐acrylonitrile), amorphous PHB, and crystalline PHB. The crystallization of PHB in the blends was influenced by the AES content in different ways, depending on the processing conditions. A blend containing 30 wt % AES presented impact resistance comparable to that of high‐impact polystyrene, and the value was about 190% higher than that of pure PHB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of dicyanate monomers containing methylene spacers
Authors: Anuradha G. , Sarojadevi M. 
Published: July 2008

AbstractThe bisphenols containing methylene spacer were prepared by treating eugenol/2‐allyl phenol with 2,6‐dimethyl phenol/guiacol/o‐cresol in the presence of AlCl3. All the bisphenols were converted to their respective cyanate esters by treating with CNBr. The structural confirmation was done by FTIR, 1H NMR, 13C NMR spectral methods, and elemental analysis. Thermal characterization was done by DSC and TGA. DSC transition shows that the Tg is in the range of 208–239°C. The Tg is highest for the cyanate ester Cy(b) with symmetric structure. The Tg of the cured network depends on the length and symmetry of the monomer, Tg being higher for shorter and the para‐substituted monomers. The T10 values are in the range of 364–381°C. The char yield is in the range of 47–53%. From the char yield, the limiting oxygen index (LOI) value was determined, which is used to confirm the flame retardancy of the cyanate ester resins. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Antimicrobial finishing of regular and modified nylon‐6 fabrics
Authors: Shalaby S. E. , AL‐Balakocy N. G. , Abdel‐Fatah O. M. , Elshafei A. M. 
Published: July 2008

AbstractA simple, efficient, and practically applicable functional approach for improvement antimicrobial properties of nylon‐6 fabrics and increase the washing durability of biofunctions was developed. This finishing approach is based on grafting of the fabrics with methacrylic acid (MAA) to create additional carboxylic groups in nylon‐6 macromolecules, followed by subsequent reaction with dimethylalklbenzyl ammonium chloride (DMABAC) solution under alkaline conditions. The carboxylic groups react with cationic agent through ionic interaction, which led to the immobilization of QAS on nylon‐6 fabrics. This immobilization was proofed through determination of nitrogen content, applying scanning electron microscopy (SEM), and FTIR microscopy. The effect of treatment conditions on salt uptake (SUT) on nylon‐6 fabrics and reaction efficiency (RE) was investigated. The antimicrobial assessment of regular and grafted with PMAA nylon‐6 fabrics treated with DMABAC revealed that both types of fabrics are characterized before washing, by quite strong biocide effect on Bacillus mycoides, Escherichia coli and Candida albicans. The role of grafting nylon‐6 fabrics before treatment with salt on durability of antimicrobial functions seems to be more significant as the samples were repeatedly washed. Even after Laundring 10 times the grafted samples could still provide 80%, 100%, and 87.5% microbial reduction against B. mycoides, E. coli and C. albicans, respectively, in contrast with 42.6%, 65.6%, and 42.5% in case of regular nylon‐6 fabrics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
Fabrication, structure, and properties of chitin whisker‐reinforced alginate nanocomposite fibers
Authors: Watthanaphanit Anyarat , Supaphol Pitt , Tamura Hiroshi , Tokura Seiichi , Rujiravanit Ratana 
Published: July 2008

AbstractCalcium alginate yarn (30 fibers) and calcium alginate nanocomposite yarn (30 fibers) containing 0.05–2.00% w/w chitin whiskers were both prepared by wet spinning process. The whiskers were prepared by acid hydrolysis of chitin from shrimp shells. The average length and width of the whiskers were 343 and 46 nm, with the aspect ratio being ∼ 7.5. Incorporation of a low amount of the whiskers in the nanocomposite fibers improved both the mechanical and the thermal properties of the fibers significantly, possibly a result of the specific interactions, i.e., hydrogen bonding and electrostatic interactions, between the alginate molecules and the homogeneously dispersed chitin whiskers. Biodegradation of the calcium alginate fibers and the nanocomposite fibers was tested in Tris‐HCl buffer solution and the same buffer solution that contained lysozyme. The addition of the chitin whiskers in the nanocomposites fibers accelerated the biodegradation process of the fibers in the presence of lysozyme, whereas the presence of Ca2+ ions in the Tris‐HCl buffer solution helped to improve the tenacity of both the alginate and the nanocomposite fibers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Kinetics of glycidyl azide polymer‐based urethane network formation
Authors: Manu S. K. , Sekkar V. , Scariah K. J. , Varghese T. L. , Mathew S. 
Published: July 2008

AbstractReactions between hydroxyl‐terminated glycidyl azide polymer (GAP) and different isocyanate curatives such as toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), and methylene diicyclohexyl isocyanate (MDCI) at various temperatures viz. 30, 40, 50, and 60°C were followed by Fourier transform infra red spectroscopy. The reactions were found to follow second‐order kinetics. With TDI and IPDI at 30°C, a two‐stage reaction was observed. For GAP‐TDI system, the second stage was slower than the first while for GAP‐IPDI system, the second stage was faster than the first indicating dominance of autocatalytic effect. The stage separation occurred due to the difference in reactivity of the isocyanate groups and was found to narrow down with increase in temperature. The viscosity build up due to the curing reaction was followed for GAP‐TDI system for comparison. The stage separation was evident in the viscosity build up also. Rheokinetic analysis done based on data generated showed a linear correlation between viscosity build up and fractional conversion. The kinetic and activation parameters evaluated from the data showed the relative difference in reactivity of the three diisocyanates with GAP. Both the approaches suggested that the reactivity of the isocyanates employed for the present study could be arranged as TDI > IPDI ≫ MDCI. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Curing reaction of amino‐terminated aqueous‐based polyurethane dispersions with triglycidyl‐containing compound
Authors: Wang Shih‐Chieh , Chen Po‐Cheng , Yeh Jen‐Taut , Chen Kan‐Nan 
Published: July 2008

AbstractAmino‐terminated anionic aqueous‐based polyurethane (PU) dispersion was obtained from NCO‐terminated PU prepolymer, which was neutralized with an excess triethylamine (TEA) and chain extended by ethylenediamine (EDA) during water dispersion process. That PU prepolymer was obtained from a polyaddition reaction of isophorone diisocyanate (IPDI), polypropylene glycol‐2000 (PPG‐2000), and 2,2′‐dimethylol propanoic acid (DMPA). This aqueous‐based PU dispersion was treated with trimethylolpropane triglycidyl ether (TMPTGE) as a latent curing agent and resulted in a self‐cured PU resin on drying. A model ring‐opening curing reaction between oxirane group of TMPTGE with terminal amino group of PU was demonstrated by glycidol with n‐butyl amine. The physical and mechanical properties as well as thermogravimetric analyses of these self‐cured PU resins were evaluated in this article. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Study on the long‐term thermal‐oxidative aging behavior of polyamide 6
Authors: Shu Ying , Ye Lin , Yang Tao 
Published: July 2008

AbstractThe long‐term thermal‐oxidative aging behavior of polyamide 6 (PA6) was studied by comparison with the stabilized sample in this work. The variation of mechanical properties of the pure and the stabilized samples of PA6 with aging time at 110°C, 130°C, and 150°C were investigated, respectively. The aging mechanism of PA6 under heat and oxygen was studied in terms of the reduced viscosity, crystallization behavior, dynamic mechanical behavior, and chemical composition through the methods of polarized light microscopy (PLM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X‐ray photoelectron energy spectrum (XPS), and so on. The results indicated that at the initial stage of aging, the molecular crosslinking reaction of PA6 dominated resulting in the increase of the mechanical strength, reduced viscosity, and the glass transition temperature of the sample. And the molecular degradation dominated in the subsequent aging process resulting in the decrease of the melting temperature, the increase of the crystallinity, and the formation of the oxides and peroxides products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Jute fiber reinforced polypropylene produced by continuous extrusion compounding, part 1: Processing and ageing properties
Authors: van den Oever M. J. A. , Snijder M. H. B. 
Published: July 2008

AbstractThis article addresses the processing and ageing properties of jute fiber reinforced polypropylene (PP) composites. The composite has been manufactured by a continuous extrusion process and results in free flowing composite granules, comprising up to 50 weight percent (wt %) jute fiber in PP. These granules have similar shape and diameter as commercially available PP granules. Rheological analysis shows that viscosity of the compounds follows the same shear rate dependency as PP and is on the same level as glass‐PP compounds. The mechanical properties show very little variation and exhibit strength and stiffness values at the upper range of competing natural fiber reinforced compounds for injection molding. The mechanical performance reduces gradually upon prolonged thermal loading and immersion in water. The low water diffusion coefficient of the 50 wt % jute‐PP composites indicates that the fibers are not forming a continuous network throughout the polymer. The jute fibers exhibit a stabilizing effect against ultra violet irradiation (UV) on PP polymer and, as a consequence, the mechanical properties of jute‐PP composites hardly decrease during an accelerated UV ageing test. Bacteria, fungi, and garden mold grow easily on the compound material, but only have a limited effect on mechanical properties. The resistance to growth of bacteria on the materials surface can be increased using a biostabilizer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis, characterization, and curing of a new acrylate‐based dental restorative resin
Authors: Ghaemy Mousa , Bekhradnia Sara , Heidaripour Maryam 
Published: July 2008

AbstractThe synthesis of monomer 1,3‐bis [(2‐hydroxy‐3‐acrylate) propyloxy]2‐hydroxy propane (BHAPP) is reported for the possible use in dental restoratives. The monomer was prepared by the reaction of acrylic acid with diglycerol diglycidyl ether (DGE) in the presence of triethyl amine as a catalyst. The progress of the reaction at 60°C followed by measuring the intensity of the epoxide absorption peak at 915 cm−1 which has reached to its minimum value after 5 h. The structure of the monomer was characterized by FTIR and 1H‐NMR. The monomer was a moderately viscous light yellow color liquid having a refractive index of 1.544. Thermal curing of the monomer in DSC in the presence of benzoyl peroxide showed exothermic peak with maximum temperature (Tp) varied from 89 to 107°C depending on the heating rate and activation energy of 83 kJ/mol. Photopolymerization of the monomer by visible light in the presence of camphorquinone and N,N‐dimethylaminoethyl methacrylate as the photoinitiating system showed maximum 60% conversion after 40 s exposure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Silk grafting with methacrylic and epoxy monomers: Thermal process in comparison with ultraviolet curing
Authors: Ferrero Franco , Periolatto Monica , Songia Michela Bianchetto 
Published: July 2008

AbstractSilk grafting with methacrylic and epoxy monomers was studied with the aim to obtain high graft yields. With both monomer types optimum operating conditions of thermal grafting in water bath were established. In particular, three epoxy monomers were tested at various concentrations, at different temperatures and reaction times, with sodium chloride or sodium thiosulphate as catalysts. Optimum yields (76–82%) were found with Araldite DY‐T for 2 h at 70°C with 3Msodium chloride. The results were compared with those obtained with the same monomers by UV curing, radical with methacrylates and cationic with the epoxy resin. The UV curing efficiency was tested by gel content determinations. Thermal and UV cured fibers were then subjected to measurements of fibroin solubility in ethanol–calcium chloride–water mixture to evaluate the crosslinking degree. Except in the case of methacrylamide, radical UV curing yielded fibers more crosslinked than thermal treatment, or crosslinked to the same extent, whereas cationic UV curing showed lower crosslinking effects. The grafted fibers were characterized through DSC measurements and FTIR‐ATR spectrometry. Finally, surface morphology of UV‐cured samples was investigated through SEM analyses which showed that the better products could be obtained with UV curing at low add‐on, mainly with dimethacrylates and Araldite DY‐T, whereas the thermal grafting seems to be preferable for high add‐on. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Impact of curing temperature on microstructures and properties of isobutylene–isoprene rubber/clay nanocomposites
Authors: Lu Yong‐Lai , Li Zhao , Mao Li‐Xin , Li Yao , Wu You‐Ping , Liang Yu‐Rong , Zhang Li‐Qun 
Published: July 2008

AbstractIn this work, the influence of curing temperature on microstructures of isobutylene–isoprene rubber/clay nanocomposites (IIRCNs) prepared by melt compounding was characterized using wide‐angle X‐ray diffraction and TEM. The gas barrier and tensile properties of IIRCN cured under different temperature were examined. The results reveal that high pressure, curing reactions, and reactions of amine intercalants with curing agents together play important roles on determining the final microstructures of cured IIRCNs. Changing curing temperature would dramatically alter intercalated structure, dispersion homogeneity, filler–rubber interaction strength, and crosslinking density of obtained IIRCN, resulting in great difference in final properties. Finally, some suggestions for the preparation of successful RCNs were proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of water‐blown polyurethane foams from liquefied cornstalk polyol
Authors: Yan Yongbin , Pang Hao , Yang Xiaoxu , Zhang Rongli , Liao Bing 
Published: July 2008

AbstractPolyurethane foams were prepared from the liquefied cornstalk polyol, which was obtained by the liquefaction of cornstalk in the presence of polyhydric alcohols using sulfuric acid as catalyst. The advisable liquefaction reaction conditions were selected by investigating their influences on the properties of liquefied cornstalk polyol, taking account of the requirement for the preparation of appropriate polyurethane foams. The influences of the contents of catalysts, water, surfactant, and isocyanate on the properties of polyurethane foams were also discussed, and feasible formulations for preparing cornstalk‐based polyurethane foams were proposed. The results indicated that the foams prepared from such liquefied cornstalk polyol exhibited excellent mechanical properties and thermal properties, and could be used as heat‐insulating materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008