bluuebunny/crossref_metadata_2025_split huggingface dataset:
New heterogeneous catalysis for the synthesis of poly(ether polyol)s
Authors: Garcia J. L. , Jang E. J. , Alper H. 
Published: October 2002

AbstractNovel double‐metal cyanide (DMC) complex catalysts were prepared with various precursors of cobalt or nickel and zinc with potassium cyanide. In the presence of an alcohol initiator, but in the absence of an organic‐binding ligand, the catalysts were highly active for the polymerization of alkyl‐ or alkenyl‐substituted epoxides to produce poly(ether polyol)s. The polymer obtained from propylene oxide showed a more isotactic structure than did the polymer made from nonselective conventional catalysts. The influence of different reaction variables were examined, including the ratio of the initiator to the substrate, the presence of a protonic agent, the temperature, as well as the concentration of the catalyst and the solvent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1553–1557, 2002
Investigation of electrical and optical properties of polyvinyl acetate doped with some polymers
Authors: Soliman L. I. , Sayed W. M. , Hendia T. A. , Amaly M. H. 
Published: October 2002

AbstractPolyglycerol (PG) and polytriethanolamine(PTEA) have been prepared. The electrical resistivity (ρ) and the optical absorption of polyvinylacetate (PVAc) doped with polyglycerol (PG), polyaniline (PA), and polytriethanolamine (PTEA) have been studied. It was found that the conduction was mainly ionic in the temperature range from 20 to 120°C. The resistivity decreased with the increase of the dopant cocentration. The optical absorption spectra were determined in the wavelength range 400–2500 nm. The analysis of the absorption spectra showed that the intensity of the bands is remarkably affected by the dopant concentration. The optical energy gap of pure PVAc and the samples containing different dopants were estimated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1558–1563, 2002
Closed‐loop recycling of postused garden chairs based on PP using the restabilization technique. I. Evaluation of processing parameters
Authors: Kartalis C. N. , Papaspyrides C. D. , Pfaendner R. 
Published: October 2002

AbstractA remelting–restabilization technique was applied to evaluate the closed‐loop recycling of postused, white pigmented, garden chairs made from CaCO3‐filled polypropylene (PP). Analysis of the randomly collected postused chairs showed only an insufficient quantity of residual active stabilizers. Different stabilization systems in selected concentrations were employed to investigate the optimum restabilization recipe for eliminating degradation effects during reprocessing. For monitoring the processing stability of the restabilized and nonrestabilized material a multiple extrusion procedure at two different reprocessing temperatures was performed. Furthermore, a repigmentation step was applied to investigate the role of the additional pigment on the processing stability of the recycled product. Finally, mechanical tests were carried out, for studying further the effect of restabilization on the mechanical performance of the recycled material. The results lead to the conclusion that restabilization for quality improvement of postused filled PP chair material during reprocessing is permitting its reuse in the original application. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2472–2485, 2002
Synthesis and characterization of aromatic polyesters and copolyesters from 4,4′‐(1‐hydroxyphenylidene)diphenol and 4,4′‐(9‐fluorenylidene)diphenol
Authors: Loría‐Bastarrachea María I. , Vázquez‐Torres Humberto , Aguilar‐Vega Manuel de J. 
Published: October 2002

AbstractTwo isophthalic polyesters from 4,4′‐(1‐hydroxyphenylidene)diphenol (BAP/ISO) and 4,4′‐(9‐fluorenylidene)diphenol (BF/ISO), and three different copolyesters containing 75, 50, and 25 mol % of BAP/ISO were synthesized by interfacial polycondensation. This preparation method yielded polymers and copolymers that produced flexible and transparent films when they were cast from solution. Proton NMR spectrometry studies showed that the isophthalic copolyesters were obtained as random copolymers with differences in comonomer composition no larger than 2.5 mol % with respect to the expected compositions. Wide‐angle X‐ray diffraction measurements indicated that all the polyesters and copolyesters were amorphous. The copolyesters showed amorphous patterns with maxima that fell between those of the polyesters. It was also found that thermal properties such as glass‐transition temperature, onset of decomposition temperature, thermal stability, dynamic mechanical storage modulus, and maximum on the α‐transition of the damping factor tan δ of BF/ISO were higher than those of BAP/ISO. The values of these thermal properties in the copolyesters fell between those of the polyesters and were dependent on the amounts of BF/ISO and BAP/ISO present in the copolyester in a linear fashion. Therefore, the thermal properties of a given copolyester can be predicted directly from the comonomers' composition. Overall, it shows that the interfacial polycondensation method is suitable to obtain these copolyesters in a controlled manner and that their properties can be tailored to be between those of the homopolyesters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2515–2522, 2002
Preparation and characterization of bismaleimide (N,N′‐bismaleimido‐4,4′‐diphenyl methane)–vinyl ester oligomer–modified unsaturated polyester interpenetrating matrices for advanced composites
Authors: Dinakaran K. , Alagar M. 
Published: October 2002

AbstractInterpenetrating networks of varying percentages of bismaleimide (BMI) in vinyl ester oligomer (VEO) modified unsaturated polyester (UP) matrices have been developed. Vinyl ester oligomer was prepared by reacting commercially available epoxy resin GY 250 (Ciba‐Geigy) and acrylic acid, and used as a toughening agent for unsaturated polyester resin. Unsaturated polyesters modified with 10, 20, and 30 wt % vinyl ester oligomer were made. The VEO toughened unsaturated polyester matrix systems, further modified with 5, 10, and 15 wt % bismaleimide (BMI). BMI–VEO–UP matrices were characterized using differential scanning calorimetry, thermogravimetric analysis, and heat deflection temperature analysis. The matrices, in the form of castings, were characterized for their mechanical properties according to ASTM methods: tensile strength, flexural strength, and unnotched Izod impact test. Data obtained from mechanical studies and thermal characterization indicate that the introduction of VEO and BMI into unsaturated polyester resin improves thermomechanical properties according to their percentage concentration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2502–2508, 2002
Cellulose/chitin films blended in NaOH/urea aqueous solution
Authors: Zheng Hua , Zhou Jinping , Du Yumin , Zhang Lina 
Published: October 2002

AbstractRegenerated cellulose/chitin blend films (RCCH) were satisfactorily prepared in 6 wt % NaOH/4 wt % urea aqueous solution by coagulating with 5 wt % CaCl2 aqueous solution then treating with 1 wt % HCl. The structure, miscibility, and mechanical properties of the RCCH films were investigated by infrared, scanning electron microscopy, ultraviolet spectroscopies, X‐ray diffraction, tensile test, and differential scanning analysis. The results indicated that the blends were miscible when the content of chitin was lower than 40 wt %. Moreover, the RCCH blend film achieved the maximum tensile strength in both dry and wet states of 89.1 and 43.7 MPa, respectively, indicating that the tensile strength and water resistivity of the RCCH film containing 10–20 wt % chitin was slightly higher than that of the RC film unblended with chitin. Structural analysis indicated that strong interaction occurred between cellulose and chitin molecules caused by intermolecular hydrogen bonding. Compared to the mechanical properties of chitin film, those of the blend films containing 10–50 wt % chitin were significantly improved. This work provided a novel way to obtain directly chitin material blended in the aqueous solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1679–1683, 2002
Radiation synthesis and application of a hydrogel based on acrylic acid and 2‐mercaptobenzimidazole
Authors: Nizam El‐Din Horia M. M. 
Published: October 2002

AbstractA hydrogel based on gamma‐radiation polymerization of acrylic acid (AAc) in the presence of 2‐mercaptobenzimidazole (MBI) and a crosslinking agent was prepared. The properties of this AAc/MBI hydrogel were characterized in terms of gel content, swelling in different solvents, structure morphology, and IR spectroscopy. Moreover, the thermal decomposition behavior of the prepared hydrogel was investigated by thermogravimetric analysis (TGA). The TGA thermograms were also used to determine the different kinetic parameters such as order of reaction and activation energy. The sorption of some divalent metal ions such as Cu2+, Pb2+, Cd2+, and Hg2+ by the AAc/MBI hydrogel also was studied. The results showed that the AAc/MBI hydrogel has a higher tendency to swell in water and polar solvents than in nonpolar solvents. The highest metal uptake by the hydrogel was found for Hg2+ and Cd2+, whereas the lowest was for Cu2+ and Pb2+ ions. The ratios between the distribution coefficients of the different metals [separation factors (SF)] indicate that the hydrogel has a high selectivity for Hg2+ over Cu2+ (SF = 10.923) and Pb2+ (SF = 19.110). However, the hydrogel prefers Hg2+ over Cd2+ (SF = 1.356) and showed a high selectivity for Cd2+ over Cu2+ (SF = 7.822) and Pb2+ (SF = 7.240). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1607–1614, 2002
Effects of surface chemistry of silica particles on secondary structure and tensile properties of silica‐filled rubber systems
Authors: Suzuki Nozomu , Yatsuyanagi Fumito , Ito Masayoshi , Kaidou Hiroyuki 
Published: October 2002

AbstractSilica particles were treated by silane coupling agents to study the effects of surface chemistry of silica particles on the secondary structure formed by silica particles in styrene–butadiene rubber (SBR). The relation between the size of secondary structure and tensile properties of silica‐filled SBR vulcanizates was also investigated. The water molecules adsorbed on the silica surface enhanced both the reactivity of the coupling agents with silanol groups on the silica surface and the condensation reaction between coupling agents. The averaged size of one agglomerate in the filled vulcanizate (Sagg) decreased with the increase of the hydrophobic character of silica particles, which were obtained by the introduction of coupling agents with alkyl groups. The initial slope of stress–strain curves for silica‐filled vulcanizates decreased with the decrease of Sagg. Further, a clear Payne effect was observed in all silica‐filled vulcanizates, with this tendency more prominent in the larger Sagg. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1622–1629, 2002
Bulk polymerization of methyl methacrylate initiated by high intensity ultrasonic irradiation and ESR study
Authors: Gu Chen‐bin , Wang Dong‐jun , Wang Xin‐qiu , Huang Yong‐ , Zhen Zhen , Liu Xin‐hou 
Published: October 2002

AbstractHigh‐intensity ultrasound was used to initiate the bulk polymerization of methyl methacrylate. The polymerization rate varied with the sonication time, the intensity of the ultrasound, and the initiator concentration of poly (methyl methacrylate) in the monomer. Electron spin resonance (ESR) spectra, obtained by the spin trapping technique, testified that free radicals were produced during the sonication process, and the concentration of radicals also changed with the sonication condition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1731–1735, 2002
The effect of nano‐sized silicate layers from montmorillonite on glass transition, dynamic mechanical, and thermal degradation properties of segmented polyurethane
Authors: Tien Yun. I. , Wei Kung Hwa 
Published: October 2002

AbstractThe glass transition temperature of the hard‐segment phase and the storage modulus of segmented polyurethane increased substantially in the presence of a small amount of tethered nano‐sized layered silicates from montmorillonite compared with their pristine state (by 44°C and by 2.8‐fold, respectively). Furthermore, the heat resistance and degradation kinetics of these montmorillonite/polyurethane nanocomposites were enhanced, as shown by thermogravimetric analysis. In particular, a 40°C increase in the degradation temperature and a 14% increase in the degradation activation energy occurred in polyurethane containing 1 wt % trihydroxyl swelling agent‐modified montmorillonite compared to that of the pristine polyurethane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1741–1748, 2002
Comprehensive experimental study of a starch/polyesteramide coextrusion
Authors: Martin O. , Avérous L. 
Published: October 2002

AbstractA comprehensive study of the three‐layer film coextrusion was performed. Plasticized wheat starch (PWS) was chosen as the film central layer, and poly(ester amide) (PEA) was used as the surface outer layers. Single‐screw extruders and a standard feedblock attached to a flat coat‐hanger die were used to prepare the three‐layer films. The layer deformation and interfacial instability phenomena, inherent to multilayer flows, were thoroughly investigated. The effect of process variables, such as viscosity ratio, extrusion rate, layer thickness, and die geometry, were studied. Encapsulation of the central layer by the skin layers readily occurred at the edges of coextruded films. The stability of PEA/PWS/PEA coextrusion flows was closely related to the shear stress at the interface. Increasing global volumetric flow rates and the die gap geometry seemed to promote instabilities. Finally, the existence of instabilities at the interface increased the adhesion strength of multilayered products, due to mechanical interlocking between adjacent layers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2586–2600, 2002
Cationic cyclization of neoprene with a diethylaluminum chloride and organic chloride catalyst system
Authors: Wang Chaoyang , Huang Xuepin , Yang Jihua 
Published: October 2002

AbstractThe cyclization of neoprene was achieved with the aid of a cationic catalyst system based on diethylaluminum chloride (Et2AlCl) and an organic chloride, allyl chloride (CH2CHCH2Cl) or benzyl chloride (C6H5CH2Cl). The main parameters of the cyclization process were investigated. Elastomers with low intrinsic viscosity, ready solubility and some gelling were obtained. Xylene was a good solvent for the cyclization process, which took place in a very short time (≤5 min). The products were characterized with IR,1H‐NMR, differential scanning calorimetry, and gel permeation chromatography. The polycyclic structure was determined. The degree of cyclization and the incorporated solvent content were estimated with a1H‐NMR method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2227–2231, 2002
Influence of a compatibilizer on the properties of polyethylene–octene elastomer/starch blends
Authors: Wu Chin‐San , Liao Hsin‐Tzu 
Published: October 2002

AbstractThe effect of a compatibilizer on the properties of corn starch‐reinforced metallocene polyethylene–octene elastomer (POE) blends was studied. The compatibility between POE and starch was improved markedly with an acrylic acid‐grafted POE (POE‐g‐AA) copolymer as a compatibilizer. Fourier transform infrared spectroscopy, X‐ray diffraction spectroscopy, differential scanning calorimetry, and scanning electron microscopy were used to examine the blends produced. The size of the starch phase increased with an increasing content of starch for noncompatibilized and compatibilized blends. The POE/starch blends compatibilized with the POE‐g‐AA copolymer lowered the size of the starch phase and had a fine dispersion and homogeneity of starch in the POE matrix. This better dispersion was due to the formation of branched and crosslinked macromolecules because the POE‐g‐AA copolymer had anhydride groups to react with the hydroxyls. This was reflected in the mechanical properties of the blends, especially the tensile strength at break. In a comparison with pure POE, the decrease in the tensile strength was slight for compatibilized blends containing up to 40 wt % starch. The POE‐g‐AA copolymer was an effective compatibilizer because only a small amount was required to improve the mechanical properties of POE/starch blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1792–1798, 2002
Fracture toughness of silica particulate‐filled epoxy composite
Authors: Adachi Tadaharu , Araki Wakako , Nakahara Takuya , Yamaji Akihiko , Gamou Masahiro 
Published: October 2002

AbstractThe relationship between the postcuring conditions and fracture toughness on three silica particulate‐filled epoxy composites was investigated. The glass transition temperature, Tg, and the fragility parameter, m, derived from the thermo‐viscoelasticity, were used to characterize the composites, which were postcured under various conditions. The glass transition temperature and fragility both depended on both of the curing conditions and the volume fraction of silica particles. The glass transition temperature increased with the postcuring time and temperature, while the fragility generally decreased as the volume fraction increased. There was no direct correlation between the glass transition temperature and fragility. The fracture toughness depended on both the glass transition temperature and fragility. The composites with a high glass transition temperature and low fragility had high fracture toughness. These results indicate that the glass transition temperature and fragility are useful parameters for estimating the fracture toughness of the silica particulate‐filled epoxy composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2261–2265, 2002
Characteristics of electrical responsive chitosan/polyallylamine interpenetrating polymer network hydrogel
Authors: Jeong Seon , Jun Park Sang , Shin Mi‐Seon , Kim Sun I. 
Published: October 2002

AbstractAn interpenetrating polymer network (IPN) hydrogel composed of chitosan and polyallylamine exhibited electric‐sensitive behavior. The chitosan/polyallylamine IPN hydrogel was synthesized by radical polymerization using 2,2‐dimethoxy‐2‐phenylacetophenone (DMPAP) and methylene bisacrylicamide (MBAAm) as initiator and crosslinker, respectively. The swelling behavior of the IPN was studied by immersion of the gel samples in aqueous NaCl solutions at various concentrations and pHs. The swelling ratio decreased with increasing concentration and pH of electrolyte solution. The stimuli response of the IPN hydrogel in electric fields was also investigated. When a swollen the IPN was placed between a pair of electrodes, the IPN exhibited bending behavior in response to the applied electric field. The IPN also showed stepwise bending behavior depending on the electric stimulus. In addition, thermal properties of the IPN were investigated by differential scanning calorimetry (DSC) and dielectric analysis (DEA). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2290–2295, 2002
Nitroxide‐mediated radical polymerization of 4‐vinylpyridine and its application on modification of silicon substrate
Authors: Chen Zhijun , Cai Jie , Jiang Xiqun , Yang Changzheng 
Published: October 2002

AbstractThe poly(4‐vinylpyridine) with hydroxyl end group and narrow polydispersity was synthesized by polymerization of 4‐vinylpyridine by the use of nitroxide initiator based on 4‐hydroxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl and azobisisobutyronitrile. The effects of different initiator amounts and reaction time on polymerization rate, molecular weight, and molecular weight distribution of the poly(4‐vinylpyridine) were investigated at bulk polymerization. The experimental results have shown that the polymerization of 4‐vinylpyridine is a controlled living free‐radical polymerization; the molecular weight is proportional to reaction time; and the molecular weight and molecular weight distribution are affected by molar ratios of [4‐hydroxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl]/[azobisisobutyronitrile]. By varying the ratio of 4‐hydroxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl to azobisisobutyronitrile, the poly(4‐vinylpyridine) with narrow polydispersity can be obtained. X‐ray photoelectron spectroscopy results show that the synthesized poly(4‐vinylpyridine) can be tethered on the surface of silicon wafer through the reaction between hydroxyl end of poly(4‐vinylpyridine) and native silicon oxide layer on the wafer surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2687–2692, 2002
Preparation and properties of water‐soluble polyester surfactants. I. Preparation and surface activity of poly(ethylene glycol)‐dimethyl 5‐sulfo‐isophthalate sodium salt polyester surfactants
Authors: Lin Li‐Huei , Chiang Chung‐Yu , Liu Hsin‐Jiant , Chen Keng‐Ming 
Published: October 2002

AbstractThe reaction of poly(ethylene glycol) (PEG, number‐average molecular weight Mn = 400‐2000) and dimethyl 5‐sulfoisophthalate sodium salt (SIPM) synthesized a series of anionic polymeric surfactants having a range of molecular weights. 1H‐NMR, FTIR, and elemental analysis were employed to characterize the structures of these compounds. Also, the influences of the PEG segment lengths of PEG/SIPM copolymers on the surface tension, foaming properties, wetting power, and dispersant properties were investigated. The experimental results indicated that the solution that contained the PEG/SIPM copolymer surfactants exhibited excellent surface‐active properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2727–2731, 2002
Supramolecular morphology of two‐step, melt‐spun poly(lactic acid) fibers
Authors: Cicero John A. , Dorgan John R. , Janzen Jay , Garrett James , Runt James , Lin J. S. 
Published: October 2002

AbstractFibers of poly(lactic acid) produced by two‐step melt spinning have been studied. The morphology is elucidated with respect to the thermal and mechanical properties of fibers produced at cold‐draw ratios of 1–8. With atomic force microscopy and small‐angle X‐ray scattering, a fibrillar morphology is found, with microfibril diameters ranging from 30 to 60 nm. Shrinkage properties indicate that, with increasing draw ratio, the fibers undergo a transition from class 2 to class 1 within the classification proposed by Keller. A supramolecular model for the morphology of the fibers is presented that entails a highly oriented skin with a core consisting of microfibrils. The orientation of the crystalline blocks within the microfibrils is similar to what has been reported for nylon fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2828–2838, 2002
Evolution of interactions between water and native corn starch as a function of moisture content
Authors: Brouillet‐Fourmann S. , Carrot C. , Lacabanne C. , Mignard N. , Samouillan V. 
Published: October 2002

AbstractThermostimulated current spectroscopy, thermogravimetric analysis, and differential scanning calorimetry (DSC) were used to study starch–water systems with moisture contents of 0–50% (on a total weight basis). DSC enabled the calculation of the amounts of bound and free water. The maximum quantity of bound water was detected for a 30% humidity sample. The existence of interactions between water and starch was proved and found to be weakened for samples containing more than 30% water. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2860–2865, 2002