bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of cryostructuration of polymer systems. XX. Foamed poly(vinyl alcohol) cryogels
Authors: Lozinsky Vladimir I. , Damshkaln Lilija G. 
Published: October 2004

AbstractFoamed poly(vinyl alcohol) (PVA) cryogels, which are formed as a result of freeze–thaw treatment of whipped PVA water solutions (polymer with MW of 69,000 Da and DD ∼99 mol % was used), were obtained and their properties were studied. The rheological characteristics and macrostructure of these gel materials were controlled by the same factors as for the ordinary nonfoamed PVA cryogels (initial polymer concentration and freezing–thawing regimes) and also by the conditions of generation of fluid PVA foams. The study of the kinetics of the freeze–thaw‐induced gel formation of these foams revealed that the temperature dependence of the efficiency of cryotropic gelation showed a maximum at about −1.5°C. The presence of low molecular weight admixtures in the initial polymer solution appears to be a rather important factor because the admixtures were capable of decreasing the stability of fluid PVA foams and weakening both foamed and nonfoamed cryogel samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1609–1619, 2001
Blend fibers of polyacrylonitrile and water‐soluble chitosan derivative prepared from sodium thiocyanate solution
Authors: Nam Chang‐Woo , Kim Young Ho , Ko Sohk Won 
Published: October 2004

AbstractA water‐soluble chitosan derivative of N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTCC), synthesized by the reaction of chitosan and glycidyltrimethyl ammonium chloride, and polyacrylonitrile (PAN) were blended using 46% (w/w) NaSCN aqueous solution as a common solvent. The total polymer concentration of blend solution was fixed at 12% (w/w), and the relative composition of PAN/HTCC in the blend solution varied from 0/100 to 80/20 by weight. The PAN/HTCC blend fibers with the appropriate physical property were prepared by a wet spinning and drawing process. The effect of HTCC content on the structural change, miscibility, and ability to be dyed of the blend fibers was investigated. The optical and scanning electron microscopic observation gave no indication of phase separation up to 20% HTCC content. Differential scanning calorimetry and dynamic mechanical measurements of the blend fibers show single glass transition temperatures that increase with increasing blend ratio of HTCC. All the experimental results exhibit that the blends are miscible on the molecular scale. The blend fibers could be dyed with an acid dye. This enhanced ability of the blend fibers to be dyed with acid dyes could be useful for one‐step dyeing when mixed with other fibers, such as wool and nylon. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1620–1629, 2001
Preparation of amorphous poly(ethylene terephthalate) from U‐polymer via a copolymerization process
Authors: Liu Su‐Huai , Zhang Shu‐Fan , Qi Zong‐Neng , Zhang Guang‐Li , Zhang Hong‐Zhi 
Published: October 2004

AbstractU‐Polymer, a kind of polyarylate, was synthesized by interfacial polycondensation method with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and bisphenol A (BPA) as raw materials. The structure of the U‐Polymer was characterized by IR and 1H–NMR spectra. Then, an amorphous poly(ethylene terephthalate) (APET) was prepared with the introduction of the U‐Polymer to the PET sequence to improve thermal and mechanical behaviors of PET via the polymerization process. The structure and property of the APET were characterized by DSC and DMA. The results showed that the APET exhibits amorphism, transparency, higher glass‐transition temperature (Tg), and higher storage modulus than that of PET. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1653–1657, 2001
Surface modification of low‐density polyethylene (LDPE) film and improvement of adhesion between evaporated copper metal film and LDPE
Authors: Kong Ju‐Shik , Lee Dong‐Jin , Kim Han‐Do 
Published: October 2004

AbstractTo improve the interfacial adhesion between evaporated copper film and low‐density polyethylene (LDPE) film, the surface of LDPE films was modified by treating with chromic acid [K2Cr2O7/H2O/H2SO4 (4.4/7.1/88.5)]/oxygen plasma. Chromic‐acid‐etched LDPE was exposed to oxygen plasma to achieve a higher content of polar groups on the LDPE surface. We investigated the effect of the treatment time of chromic acid in the range of 1–60 min at 70°C and oxygen plasma in the range of 30–90 sec on the extent of polar groups created on the LDPE. We also investigated the surface topography of and water contact angle on the LDPE film surface, mechanical properties of the LDPE film, and adhesion strength of the evaporated copper metal film to the LDPE film surface. IR and electron spectroscopy for chemical analysis revealed the introduction of polar groups on the modified LDPE film surface, which exhibited an improved contact angle and copper/LDPE adhesion. The number of polar groups and the surface roughness increased with increasing treatment time of chromic acid/plasma. Water contact angle significantly decreased with increasing treatment time of chromic acid/plasma. Combination treatment of oxygen plasma with chromic acid drastically decreased the contact angle. When the treatment times of chromic acid and oxygen plasma were greater than 10 min and 30 sec, respectively, the contact angle was below 20°. With an increasing treatment time of chromic acid, the tensile strength of the LDPE film decreased, and the film color changed after about 10 min and then became blackened after 30 min. With the scratch test, the adhesion between copper and LDPE was found to increase with an increasing treatment time of chromic acid/oxygen plasma. From these results, we found that the optimum treatment times with chromic acid and oxygen plasma were near 30 min and 30 sec, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1677–1690, 2001
Novel regenerated cellulose fibers from rice straw
Authors: Lim Sang Kyoo , Son Tae Won , Lee Dong Won , Park Bong Kuk , Cho Kyu Min 
Published: October 2004

AbstractRegenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/N‐methylmorpholine‐N‐oxide (MMNO) solution. X‐ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). This observation indicates a potential utility of rice straw as an alternative to wood pulp as a cellulose‐based fiber material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1705–1708, 2001
Preparation of bipolar membranes. II
Authors: Hao Ji Hua , Yu Lixin , Chen Cuixian , Li Lin , Jiang Weijun 
Published: October 2004

AbstractThe bipolar multilayer membrane was prepared by a new technique. The interfacial layer and cation layer were formed by only one step. The anion and cation layers were made from the same material from which chloromethylated polysulfone was used as a basic material. The bipolar membranes were composed of a solvent‐resistant anion layer with crosslinking matrix by the reaction of chloromethylated polysulfone in DMF with diamine; an ultrathin interfacial layer from chloromethylated polysulfone solution in DMF, containing cation‐exchange resin and both quaternary and nonquaternary amine groups; and a cation layer from chloromethylated polysulfone dispersing cation resin powder. The prepared bipolar membrane exhibits a lower voltage drop over 100 mA/cm2 and stable performances at a long‐term operation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1733–1738, 2001
On the viscoelastic properties of poly(vinyl alcohol) and chemically crosslinked poly(vinyl alcohol)
Authors: Park Jun‐Seo , Park Jang‐Woo , Ruckenstein Eli 
Published: October 2004

AbstractPoly(vinyl alcohol)(PVA) films chemically crosslinked with glutaraldehyde(GA) in the presence of HCl were prepared by casting from aqueous solutions. The PVA and PVA gels were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA); their swelling characteristics and tensile strength were also determined. The DSC results for the gels displayed depressions of the melting and crystallization temperatures, as well as a decrease of the heat of fusion, when compared to those of PVA free of crosslinker. The DMA analysis revealed that: (1) The glass transition temperature of the wet PVA was lower than that of the dry one, indicating that the water had a plasticizing effect. (2) The gels had a lower glass transition temperature than PVA. (3) The glass transition temperature of the wet gels increased with increasing crosslink density. Possible explanations are provided for these observations. Whereas the thermogravimetric curves of PVA exhibited a single degradation peak, two degradation peaks were detected for the crosslinked PVA. The wet PVA and PVA gels displayed lower tensile strengths and higher elongations than the dried ones. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1816–1823, 2001
Acylation of silk and wool with acid anhydrides and preparation of water‐repellent fibers
Authors: Arai T. , Freddi G. , Innocenti R. , Kaplan D. L. , Tsukada M. 
Published: October 2004

AbstractSilk and wool fibers were acylated with two acid anhydrides, dodecenylsuccinic anhydride (DDSA) and octadecenylsuccinic anhydride (ODSA), at 75°C with N,N‐dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) as the solvent, the latter of which allowed higher weight gains to be reached. The weight gain and acyl content of wool was always higher than that of silk. Tensile properties of silk remained unchanged regardless of weight gain, whereas wool displayed a noticeably higher extensibility at high weight gain. Fine structural changes of acylated wool were detected by DSC analysis. Moisture regain and water retention of acylated silk and wool decreased significantly, whereas water repellency increased. SEM analysis showed the presence of foreign material firmly adherent to the surface of both silk and wool, whose amount increased with increasing weight gain. These deposits were attributed to the presence of the modifying agents at the fiber surface on the basis of the characteristic IR bands. The possible application of silk and wool fibers acylated with DDSA or ODSA for the preparation of water‐repellent textile materials is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2832–2841, 2001
Structure of carboxylated acrylonitrile‐butadiene rubber (CNBR)–clay nanocomposites by co‐coagulating rubber latex and clay aqueous suspension
Authors: Wu You‐Ping , Zhang Li‐Qun , Wang Yi‐Qing , Liang Yi , Yu Ding‐Sheng 
Published: October 2004

AbstractCarboxylated acrylonitrile‐butadiene rubber (CNBR)–clay mixtures were prepared by co‐coagulating rubber latex and clay aqueous suspension, then combining the mixtures with a rubber ingredient and vulcanizing by a traditional rubber mixing processing procedure. Transmission electron microscopy (TEM) showed that the silicate layers of clay were delaminated or intercalated with CNBR and dispersed in the CNBR matrix at a nanometer level during co‐coagulating. X‐ray diffraction indicated that the amount of CNBR intercalating between the layers increased with the increase of content of clay in CNBR, which is in contrast with the results of other studies. Some reasons were put forward for this discrepency. The aspect ratio (width/thickness) of the platelet inclusions was reduced and the silicate layers were aligned more orderly during the compounding operation on an open mill. The intercalated CNBR, on co‐coagulating, still remained within the interlayer space after curing. In these nanocomposites, the particles of silicate layers were dispersed at the nanometer level and the structure was a combination of delaminated and intercalated silicate layers dispersed in the continuous CNBR matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2842–2848, 2001
Mechanochemical polymerization of styrene initiated by the grinding of quartz
Authors: Hasegawa Masahiro , Kimata Mitsumasa , Kobayashi Shun‐Itsu 
Published: October 2004

AbstractThe polymerization of styrene mechanochemically initiated by the wet grinding of quartz was attempted by using a vibrating ball mill with a laboratory scale. The effect of the grinding of quartz on the polymerization of the styrene was investigated by characterizing the polymer formed and the quartz ground. The results showed that styrene could also mechanochemically polymerize by the resulting active species of the grinding of quartz as well as methyl methacrylate. The polymerization was found closely related to the total surface area of the ground quartz. The molecular weight distributions of the polymer formed were not simply unimodal and remarkably broader than those of the methyl methacrylate. It was suggested that the polymerization of the styrene proceeded with a cationic active species from the experimental results and discussions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2849–2855, 2001
Using field theory to measure surface resistivity of high‐resistance polymeric films
Authors: Tsai Peter P. , Bresee Randall R. 
Published: October 2004

AbstractTheoretical expressions based on Ohm's law for field theory were derived to measure surface resistivity of high‐resistance polymer films using parallel plate and concentric circular electrodes. Experimental measurements of resistivity were compared to experimental measurements using conventional expressions based on Ohm's law for circuit theory. Expressions based on Ohm's law for circuit theory were found to be inadequate for measuring surface resistivity. The surface resistivity of high‐resistance films can be accurately measured if electric field theory is used to include the effects of electrode structure, if relative humidity (RH) and temperature are controlled, if the level of applied voltage is limited, and if the measuring system is shielded from extraneous electric and magnetic fields. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2856–2862, 2001
Encapsulation efficiency and release kinetics of solid and liquid pesticides through urea formaldehyde crosslinked starch, guar gum, and starch + guar gum matrices
Authors: Kumbar Sangamesh G. , Kulkarni Anandrao R. , Dave Ashok M. , Aminabhavi Tejraj M. 
Published: October 2004

AbstractThis article presents our preliminary experimental data on the release kinetics and encapsulation efficiency of urea formaldehyde (UF) crosslinked matrices of starch (St), guar gum (GG), and starch + guar gum (St + GG) for the controlled release of solid (chlorpyrifos) and liquid (neem seed oil) pesticides. The data reveal variable release rates in relation to the polymer type and especially the pesticide type. It is possible to slow the release rates of pesticides using cheaply available materials such as starch and guar gum. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2863–2866, 2001
Control of resin release from particleboards by gamma irradiation. I. Thermal decomposition behavior and structure morphology
Authors: El‐Naggar A. M. , Kandeel K. A. , Khafaga M. R. , Zahran A. H. 
Published: October 2004

AbstractThe release or emission of resins from pressed particleboards, modified through gamma radiation, was characterized in terms of the thermal decomposition (TGA) and structure morphology (SEM). Particleboards, based on some farm residues and some polymers as adhesives, were first made by thermal compression in a hot press at 120°C and subsequently exposed to various doses of gamma irradiation. In general, gamma irradiation improves the thermal stability of the particleboards regardless of the type of the farm residues or the type of adhesive. Meanwhile, the thermal stability was found to increase with increasing irradiation dose as shown by the percentage loss in weight at different decomposition temperatures and the temperatures of the maximum values of the rate of reaction. The results showed that the particleboards based on cotton or flax stalks and polystyrene (PS) displayed higher thermal stability than did those based on the epoxy resin (E150). The particleboards based on wood sawdust and the E150 resin showed higher thermal stability than did those based on PS. SEM observations of the fracture surfaces of the different particleboards give further support to the improvement in the thermal properties after exposure to gamma radiation. In this regard, the pores and distances between the base material were coated with radiation‐crosslinked or ‐grafted E150 resin, particularly in the case of wood sawdust boards. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2869–2881, 2001
Synthesis of macroazoinitiator by direct polycondensation for block copolymerization of styrene and butadiene
Authors: Simon Joshy , Bajpai Anjali 
Published: October 2004

AbstractMacroazoinitiator (MAI) was prepared from hydroxy‐terminated polybutadiene (HTPB) and 4,4′‐azobis‐4‐cyanopentanoic acid (ACPA) by direct polycondensation in the presence of 1‐methyl‐2‐chloropyridinium iodide (MCPI) at room temperature. This MAI proved to be an effective initiator for thermal polymerization of styrene at 60°C. The resulting products were characterized by viscosity measurements and both IR and NMR spectral studies. The ratio of styrene and butadiene units was calculated from NMR spectral data and scanning electron micrography. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2922–2933, 2001
Application of phase dispersion–crosslinking synergism on recycling commingled plastic wastes
Authors: Fang Zhengping , Zeng Minfeng , Cai Guoping , Xu Chengwei 
Published: October 2004

AbstractA tetra‐component blend, consisting of low‐density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS), was studied as a model system of commingled plastic wastes (LDPE/PVC/PP/PS, mass ratio: 70/10/10/10). Effects of chlorinated polyethylene (CPE), ethylene–propylene–diene monomer (EPDM), styrene–butadiene–styrene (SBS), and their mixture (CPE/EPDM/SBS, mass ratio: 2/2/2) on the mechanical properties and morphology of the system were investigated. With addition of several elastomers and their mixture, the tensile strength of the blends decreased slightly, although both the elongation at break and the impact strength increased. Among these elastomers, EPDM exhibited the most significant impact modification effect for the tetra‐component blends. SBS and the mixture have a good phase‐dispersion effect for the tetra‐component blend. By adding a crosslinking agent [dicumyl peroxide (DCP)], the mechanical properties of the tetra‐component blends also increased. When either SBS or the mixture was added to the blend together with DCP, the probability that the crosslinking agent (DCP) would be at the interface improved because of the phase‐dispersion effect of SBS. Therefore, more co‐crosslinked products will form between LDPE and other components. Accordingly, remarkable improvement of the interfacial adhesion and hence the mechanical properties of the tetra‐component blends occurred. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2947–2952, 2001
Novel rapid‐cure adhesives for low temperature using thiirane compound
Authors: Chino Keisuke , Suga Kazuo , Ikawa Masahiro , Satoh Hajime 
Published: October 2004

AbstractWe investigated improvement of workability (viscosity), storage stability, and curing ability of thiirane resin for adhesive applications. The viscosity of bisphenol‐F thiirane resin was lower than that of bisphenol‐A thiirane resin, especially at low temperatures, thus improving ease of handling. Addition of diphenyl decyl phosphite improved its storage stability to a level similar to that of bisphenol‐A epoxy resin. The curing of bisphenol‐F thiirane resin increased three times faster by adding 2,4,6‐tris(dimethylaminomethyl)phenol (DMP‐30) as a tertiary amine. In applications of this new thiirane resin as civil and architectural adhesives, a superior curing ability at low temperature was attained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2953–2957, 2001
Miscibility of segmented polyurethane/poly(vinyl chloride) blends
Authors: Sudaryanto  , Nishino Takashi , Ueno Masaki , Asaoka Seiji , Nakamae Katsuhiko 
Published: October 2004

AbstractMiscibilities of segmented polyurethanes (SPUs) and poly(vinyl chloride) (PVC) or functionalized poly(vinyl chloride) (FPVC) were studied with dynamic mechanical analysis, differential scanning calorimetry, and X‐ray diffraction. Mechanical properties of the blends were also studied with tensile measurements. The miscibility of the blends depended greatly on the hard‐segment content of SPU and the existence of the functional groups. The combination of SPU with a low hard‐segment content and PVC with functional groups made the blend system miscible. Moreover, controlling the blend composition of SPU/FPVC allowed us to modify the mechanical properties of SPU, where the elongation at break was multiplied without a significant change in its tensile strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3022–3029, 2001
Swelling behavior of NR/EPDM rubber blends under compression strain
Authors: Botros S. H. , El Sayed A. Mounir 
Published: October 2004

AbstractThe effect of different blend compositions of natural rubber (NR)/ethylene–propylene diene monomer rubber (EPDM) on the swelling behavior of that blend in motor oil under compression strain was investigated. The compression recovery of all blend ratios investigated had positive values at low applied compression values (3%). However, at high compression values (18 and 35%), the compression recovery had negative values. The lower weight uptake of motor oil was shown by the EPDM vulcanizate, whereas the 25/75 NR/EPDM blend showed the highest compression recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3052–3057, 2001
Dimethylammonium dimethyldithiocarbamate‐accelerated sulfur vulcanization. II. Vulcanization of rubbers and model compound 2,3‐dimethyl‐2‐butene
Authors: Shumane M. , Gradwell M. H. S. , Mcgill W. J. 
Published: October 2004

AbstractRubber and model compound 2,3‐dimethyl‐2‐butene were vulcanized for various times with dimethylammonium dimethyldithiocarbamate [(dma)dmtc]‐accelerated sulfur formulations in the absence of ZnO. Model compound systems were analyzed by HPLC, and no reaction intermediates containing pendent groups were found. Crosslinked sulfides, characterized by 1H‐NMR, were found to be essentially bis(alkenyl). Residual curatives were extracted from rubber compounds vulcanized for various times and analyzed by HPLC. Compounds, cured to various crosslink densities, were found to crystallize readily in a density column at subambient temperatures. This supports evidence from model compound systems that pendent groups are largely absent from vulcanizates. It is suggested that a reaction mechanism, similar to that applicable to zinc dimethyldithiocarbamate‐accelerated sulfur vulcanization, may be applicable with (dma)dmtc accelerated formulations. Very limited crosslinking occurred on heating compounds under vacuum, and this can be attributed largely to the rapid loss of (dma)dmtc from rubber at elevated temperatures. However, the slower rate of crystallization on cooling of the gels, compared to the rate in press‐cured vulcanizates of similar crosslink density, was interpreted as evidence that some pendent groups did form during heating with (dma)dmtc/sulfur. Crosslinking of such pendent groups may be inhibited by the loss of (dma)dmtc, that, like zinc dimethyldithiocarbamate, may catalyze their crosslinking, and/or to the loss under vacuum of dimethyldithiocarbamic acid that would form thiol pendent groups that would rapidly crosslink with thiuram pendent groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3074–3083, 2001