bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contribution of adsorptive or acid–base interaction between phenol molecules and polyvinylpyridine membrane to the large permeability of phenol through the membrane
Authors: Uramoto Hiromu , Kawabata Nariyoshi 
Published: April 2003

AbstractPermeability of phenol from aqueous solution to organic solvent through a microporous membrane made of cross‐linked poly (4‐vinylpyridine) (polyvinylpyridine membrane) was about 12 times larger than that through a microporous membrane made of polyethylene (polyethylene membrane) having similar thickness, porosity, and mean pore diameter with those of polyvinylpyridine membrane. Adsorptive or acid–base interaction between phenol molecules and polyvinylpyridine membrane was shown to play an important role in this unusally rapid permeation of phenol through the membrane. The amount of phenol contained in polyethylene membrane per unit volume of the pores was about six times larger than the phenol concentration in the feed aqueous solution. However, the amount of phenol contained in polyvinylpridine membrane per unit volume of the pores was 80–260 times larger than the feed phase concentration. The rapid permeation of phenol through poly‐vinylpyridine membrane was thus explained in terms of the extensive enrichment of phenol in the membrane due to the adsorptive or acid–base interaction between phenol molecules and the membrane. © 1993 John Wiley & Sons, Inc.
Bridging the PE lifetime under fatigue and creep conditions with its crystallization behavior
Authors: Kadota K. , Chum S. , Chudnovsky A. 
Published: April 2003

AbstractThe service lifetime for several linear polyethylene copolymers was studied by fatigue‐type accelerated tests. The material morphology and crystallization behavior were correlated with the lifetime and the failure modes. The correlation is based on the rate constant of material degradation (RCMD) recently introduced by the authors within a mathematical model for crack layer growth kinetics. RCMD is found to depend on the loading conditions (e.g., creep or fatigue) and on material morphology reflected in crystallization kinetics. The ratio of RCMDs for fatigue and creep is a scaling factor that allows one to correlate fatigue and creep lifetimes. The dependence of the RCMD's ratio on the morphological features associated with the primary and secondary crystallization kinetics is also reported in this paper. © 1993 John Wiley & Sons, Inc.
An evaluation of the DAWN‐B light scattering unit from wyatt technology: Suggested calibration, normalization, and clarification procedures
Authors: Yunan Wan , Zhongde Xu , Li Jianbo , Rosenblum William M. , Mays Jimmy W. 
Published: April 2003

AbstractProper normalization, calibration, and sample clarification procedures for use with the Wyatt Technology DAWN‐B laser light scattering photometer are described. The utility of the proposed methods is confirmed by comparing results obtained on the solution properties of polystyrene standards in three different solvents (toluene, tetrahydrofuran, and methyl ethyl ketone) with results from the literature and generated using a Chromatix KMX‐6 low‐angle light scattering photometer. © 1993 John Wiley & Sons, Inc.
Surface graft polymerization onto silicone
Authors: Iwata Hiroo , Isozaki Shuji 
Published: April 2003

AbstractA method was developed for surface graft polymerization onto silicone. A silicone prepolymer carrying vinyl groups, which can be cured by a free‐radical mechanism, was used. Acrylamide can be easily graft polymerized by simply heating the films made of a mixture of the silicone prepolymer and peroxide in an acrylamide monomer solution using an autoclave. Any complicated procedures, such as thorough degassing of the silicone films and the monomer solution, and sealing them into a glass ampoule, are not necessary. The grafted layer uniformly covered the silicone surface. The surface properties of the silicone become hydrophilic and slippery after grafting of the poly(acrylamide). © 1993 John Wiley & Sons, Inc.
Instrumented izod impact testing
Authors: Slavin S. E. , Beswick G. T. 
Published: April 2003

AbstractThe notched Izod impact test is the most prevalent technique used to characterize the effects of high‐impulse loads on polymeric materials. In order to extract ancillary information concerning fracture properties in addition to the total fracture energy, an instrumented version of this test is examined. Oscillations in the load signal, which severely degraded the utility of the data for materials fracturing in a brittle manner, are determined to be the result of specimen vibration caused by the impact of the hammer. Placement of a felt cushion on the face of the hammer is shown to eliminate these oscillations and the effects of the felt on the load‐time information are shown to be minimal. Finally, peak load data extracted from instrumented Izod tests employing felt padding, is used to determine the stress‐intensity factor for several plastics of commercial interest. © 1993 John Wiley & Sons, Inc.
Polymerization blending for compatible poly(ether sulfone)/aramid blend based on polycondensation of an N‐silylated aromatic diamine with an aromatic diacid chloride in poly(ether sulfone) solution
Authors: Hayashi Hideo , Nakata Shoichi , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractPoly(ether sulfone) (PES) and poly[N,N′‐(oxydi‐p‐phenylene)isophthalamide] (44I) were blended readily by the polymerization‐blending method; i.e., N,N′‐bis(trimethylsilyl)‐substituted bis(4‐aminophenyl) ether was reacted with isophthaloyl chloride in the PES solution in DMAc, and the resulting mixture was directly cast into films. The procedure afforded transparent films over the entire PES/44I composition range. Homogeneous mixing of the component polymers in the form of films was shown by a single glass transition temperature, whereas a conventional solution‐blending method afforded less compatible films in the PES‐rich composition. This was also supported by morphological and infrared studies. The mechanical properties of the blend films, particularly the elongation‐at‐break, were improved by using the polymerization‐blending method. © 1993 John Wiley & Sons, Inc.
Sorption of water in nylon 6‐clay hybrid
Authors: Kojima Yoshitsugu , Usuki Arimitsu , Kawasumi Masaya , Okada Akane , Kurauchi Toshio , Kamigaito Osami 
Published: April 2003

AbstractVarious nylon 6‐clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCHs and NCHPs, respectively, have been synthesized. Sorption of water in those hybrids was measured to estimate the resistance to water permeation. The diffusion coefficient D and the partition coefficient K were obtained from the sorption curves. The resistance to water permeation of NCH was superior to that of nylon 6 because of a decrease in D. In NCHP, saponite had a smaller effect on the increase of the resistance. The diffusion coefficients in NCH and NCHP decreased with an increase in the amount of clay minerals. It was found that those diffusion coefficients were well described by the contribution of the constrained region calculated from the storage and the loss modulus at the glass transition temperature. According to the mixing law, the following equation was obtained between the diffusion coefficient D and the fraction of the constrained region C, D = Da(1 – C)1/n, where the values of Da (diffusion coefficient in amorphous nylon 6) and n (morphology parameter) were 12.6 X 10−7cm2/s and 0.585, respectively. © 1993 John Wiley & Sons, Inc.
Polymer crystallization kinetics: Poly(ethylene terephthalate) and poly(phenylene sulfide)
Authors: Ravindranath K. , Jog J. P. 
Published: April 2003

AbstractAnalysis of isothermal crystallization data of PET and PPS was carried out using Avrami and Tobin models. The models gave fractional values of exponent n and the standard deviation varied between 1 and 4%. No improvement in the standard deviation could be obtained even after incorporating the nucleation rate in these models. The Hillier model gave a good fit only to the isothermal crystallization data of PET. A simple model considering primary and secondary crystallization has been proposed. The model is verified using isothermal crystallization data of PPS. © 1993 John Wiley & Sons, Inc.
Oriented PP‐PS composites obtained by polymerization of styrene inside oriented PP matrices. I. Dispersion of PS and the composites' orientation
Authors: Trznadel M. , Pluta M. , Kryszewski M. 
Published: April 2003

AbstractDispersion of polystyrene (PS) and the molecular orientation of the polypropylene–polystyrene (PP–PS) composites acquired by the in situ polymerization of styrene in the oriented PP matrices were characterized by microscopic observations, birefringence measurements, and differential scanning calorimetry. It has been shown that applied processing of the “envelope” polymerization leads to obtaining oriented composites with large contents and the specific dispersion of PS. Some composites exhibit a substantial gradient of PS concentration and a gradient of molecular orientation, both strongly dependent on the initial structure of the oriented PP matrix. The modification of the PP structure taking place during processing does not disturb the orientation of the matrices deformed to the higher draw ratios. The structural changes of the oriented PP induced by processing are reflected in the shrinkage behavior and mechanical properties discussed in the second part of this paper. © 1993 John Wiley & Sons, Inc.
Rheological behavior of short carbon fiber‐filled thermoplastic elastomer based on styrene–isoprene–styrene block copolymer
Authors: Roy D. , Gupta B. R. 
Published: April 2003

AbstractThe rheological behavior of styrene–isoprene–styrene block copolymer filled with short carbon fibers has been studied with the Monsanto Processability Tester (MPT). Carbon fibers of 6 mm length were used in the range of 0–20 phr. The rheological studies were carried out in the temperature range of 150–180°C and the shear rate range of 50.6–401.2 s−1 using three different capillaries with varying L/D ratio. The die swell was automatically recorded using a laser scanning system attached to the MPT. The results show that the composites behave as pseudoplastic materials and follow the power‐law model. The shear viscosity of the composites decreases up to 10 phr fiber loading and then either increases or remains constant with further increase of fiber concentration. The die swell decreases with increase of fiber loading and L/D ratio of the capillary. © 1993 John Wiley & Sons, Inc.
Surface modification of polyethylene and polypropylene by ion implantation
Authors: Švorčík V. , Rybka V. , EndrŠt R. , Hnatowicz V. , Kvítek J. , Seidl P. 
Published: April 2003

AbstractThe creation of oxidized structures and double bonds in polyethylene (PE) and polypropylene (PP) samples implanted with P+ ions was studied. The surface polarity and the electrical conductivity of the ion‐implanted polymers were also examined. As a result of the ion implantation, the polymer macromolecules are broken up and the material is degraded. An oxygen penetration into the radiation‐damaged polymers is also observed, with PE being more vulnerable to the oxidation. The ion‐implanted PP exhibits higher surface polarity and sheet conductivity compared to that of PE. © 1993 John Wiley & Sons, Inc.
Anionic polyurethane ionomer for one‐step electrosynthesis of conductive composites
Authors: Robila Gabriela , Ivǎnoiu Maria , Buruiana Tinca , Buruiana E. C. 
Published: April 2003

AbstractA water soluble ionomer with natrium propanesulfonate groups was prepared based on a linear polyurethane with high content of NHCOO structures. This compound was used both as macromolecular electrolyte and dopant ion in electrochemical polymerization of pyrrole, obtaining a molecular level polypyrrole‐propanesulfonate polyurethane composite with electroconductive properties. © 1993 John Wiley & Sons, Inc.
Lipoprotein lipase immobilization onto porous polyvinyl alcohol beads
Authors: Hayashi Toshio , Hyon Soung‐Hyu , Cha Won‐Ill , Ikada Yoshito 
Published: April 2003

AbstractWater‐insoluble proteases were prepared by immobilizing lipoprotein lipase (LPL) onto the surface of porous polyvinyl alcohol (PVA) beads by covalent fixation. The relative activity of the immobilized proteases was found to remain high toward small ester substrates, p‐nitrophenyl laurate (pNPL). The relative activity of the immobilized LPL by cyanogen bromide (CNBr) method decreased gradually with the decreasing surface concentration of the immobilized LPL on the porous PVA beads. On the contrary, the immobilized LPL by hexamethylene diisocyante (HMDI) method gave an almost constant activity for the substrate hydrolysis within the surface concentration region studied and gave higher relative activity (RA) than that by the CNBr method. The Michaelis constant, Km, and the maximum reaction velocity, Vm, were estimated for the free and the immobilized LPL. The apparent Km was larger for the immobilized LPL than for the free one, and Vm was smaller for the immobilized LPL. The pH, thermal, and storage stabilities of the immobilized LPL were higher than those of the free ones. The initial enzymic activity of the immobilized LPL maintained almost unchanged without any leakage and inactivation of LPL when the batch enzymic reaction was performed repeatedly, indicating excellent durability of the immobilized LPL. © 1993 John Wiley & Sons, Inc.
Tensile strain rate effect in mechanical properties of dummy HTPB propellants
Authors: Chung H. L. , Kawata K. , Itabashi M. 
Published: April 2003

AbstractThe tensile strain rate effect in tensile strength and elongation at break for a series of filled dummy hydroxy‐terminated polybutadiene (HTPB) propellant binders was studied. The data were obtained at various tensile strain rates from 10−4 to 10−1 s−1 on two types of specimens at room temperature. The “high velocity ductility” behaviour, which is qualitatively similar to those of unfilled elastomers, was revealed. This means that the breaking strain increases markedly at elevated strain rates. For “Bukkon‐type” and rod‐shaped specimens, test results are consistent with each other. The fact that the increased filled solids level leads to a decreased breaking elongation capability and an increased tensile strength was obviously found. © 1993 John Wiley & Sons, Inc.
Relaxations of bisphenol A‐based epoxides cured with aliphatic diamines
Authors: Matsukawa Mami , Okabe Hirotaka , Matsushige Kazumi 
Published: April 2003

AbstractThe main α and sub β relaxations in bisphenol A‐based epoxides cured by two kinds of aliphatic diamines were examined in wide temperature and frequency ranges by using middle‐frequency dynamic, dielectric, and ultrasonic measuring systems. The obtained temperature–frequency correlation maps revealed an Arrhenius‐type behavior for the β relaxation with apparent activation energy of 16 kcal/mol. For the α relaxation, the maps were in good agreement with the W.L.F. equation. Owing to the similarity of structure in these resins, both maps showed the same tendencies. © 1993 John Wiley & Sons, Inc.
The removal of color from effluents using polyamide–epichlorohydrin‐cellulose polymer. III. Use in anionic dye removal in a batch process
Authors: Hwang M. C. , Chen K. M. 
Published: April 2003

AbstractPolyamide–epichlorohydrin–cellulose (PAE–Cell) can adsorb substantial quantities of several direct dyes and acid dyes from aqueous solutions using a batch process. The ad‐sorption kinetics of these dyes on PAE–Cell was studied using Langmuir and Freundlich isotherm equations at different temperatures. Other adsorption parameters studied were initial dye concentration, the pH of the solution, particle size, treated time, and salt added. The PAE–Cell was found to have monolayer equilibrium saturation capacities of more than 500 mg dye per PAE–Cell for these anionic dyes. These results show that PAE–Cell polymers exhibit better capacity than do some types of commercial activated carbon. © 1993 John Wiley & Sons, Inc.
The development of a mathematical model for the pultrusion of blocked polyurethane composites
Authors: Ma Chen‐Chi M. , Chen Chin‐Hsing 
Published: April 2003

AbstractThe thermokinetic behavior of blocked polyurethane‐based composites during the pultrusion of glass‐fiber reinforced composites is investigated utilizing a mathematical model accounting for the heat transfer and the heat generation during curing. The equations of continuity and energy balance, coupled with a kinetic expression for the curing system, are solved using a finite difference method to calculate the temperature and conversion profiles in the thickness direction in a rectangular pultrusion die. A kinetic model, dP/ dt = A exp(−E/RT) (1−P)nPm, was proposed to describe the curing behavior of a blocked polyurethane resin. Kinetic parameters for the model were obtained from dynamic differential scanning calorimetry (DSC) scans using a multiple regression technique, which was able to predict the effects of processing variables on the pultrusion. The effects of process variables (e.g., pulling rate, die temperature, and die thickness) on the performance of the pultrusion are also evaluated. © 1993 John Wiley & Sons, Inc.
Structural analysis of methyl methacrylate‐grafted silk fibers
Authors: Tsukada Masuhiro , Kasai Nobutami , Freddi Giuliano 
Published: April 2003

AbstractThe structural changes of silk fibers grafted with methyl methacrylate (MMA) were investigated in relation to the weight gain. Both the refractive indices, parallel and perpendicular to the fiber axis, decreased with increasing weight gain, although the former showed a step drop in the weight gain range of 0–30%. Accordingly, birefringence and the isotropic refractive index also decreased, suggesting a lower degree of molecular orientation and crystallinity of MMA‐grafted silk fibers. However, X‐ray diffraction curves demonstrated that the crystalline structure remained unchanged, regardless of MMA grafting, implying that the MMA polymer attached preferentially within the amorphous regions of the fiber. Tensile strength and elongation at break of the grafted silk fibers, measured in dry and wet states, gradually decreased over the weight gain range examined. MMA‐grafted silk fibers in wet state exhibited comparatively lower values of strength and elongation, though the hydrophobicity, induced by the grafted polymer, resulted in an attenuation of the differences, especially at high weight gains. TMA analysis demonstrated that the onset temperature of the final extension shifted to a higher value, in the weight gain range 30–50% Dynamic mechanical measurements showed that the thermally induced molecular movement of MMA‐grafted silk increased, as illustrated by the trend of both dynamic storage and loss modulus curves. © 1993 John Wiley & Sons, Inc.
Bacterial cellulose membrane as separation medium
Authors: Shibazaki Hideki , Kuga Shigenori , Onabe Fumihiko , Usuda Makoto 
Published: April 2003

AbstractA thin membrane of bacterial cellulose (BC) obtained fromAcetobacterculture was tested for its performance as a dialysis membrane in aqueous systems. The BC membrane showed superior mechanical strength to that of a dialysis‐grade regenerated cellulose membrane, allowing the use of a thinner membrane than the latter. As a result, the BC membrane gave higher permeation rates for poly(ethylene glycols) as probe solutes. The cutoff molecular weight of the original BC membrane, significantly greater than that of regenerated cellulose, could be modified by concentrated alkali treatments of the membrane. The nature of the change at the ultrastructural level caused by the alkali treatments was studied by X‐ray diffraction and scanning electron microscopy. © 1993 John Wiley & Sons, Inc.
Reaction mechanisms, microstructure, and fracture properties of thermoplastic polysulfone‐modified epoxy resin
Authors: Min B.‐G. , Hodgkin J. H. , Stachurski Z. H. 
Published: April 2003

AbstractThe microstructure and fracture properties of diglycidyl ether of bisphenol A (DGEBA) epoxy resins modified with phenolic hydroxyl‐terminated polysulfone (PSF) and cured with diaminodiphenyl sulfone (DDS) hardener have been investigated as a function of the molecular weight and concentration of PSF. The microstructure changed from a typical particulate structure to a phase‐inverted structure as the molecular weight and/or the concentration of the modifier increased. The fracture toughness, measured by compact tension tests, increased with the microstructural changes toward the phase‐inverted structure. The microstructural changes observed have been interpreted in terms of variation in the reaction mechanisms as determined by near‐infrared spectroscopy. The level of minor reactions such as etherification and homopolymerization reactions increased with increasing molecular weight and/or concentration of the modifier, in line with the tendencies observed in microstructure and fracture toughness. In the system containing 20 wt% of Mn 10,000 PSF, about 30% of the epoxy groups were consumed by etherification and homopolymerization reactions, whereas none of these reactions occurred in the unmodified system. The increase in minor reactions in the modified systems may be to be due to the restricted molecular mobility, resulting from the increase of system viscosity caused by the modification. This increase in viscosity also reduced the rate of phase separation. The degree of heterogeneity in the epoxy network must increase with the increasing side reactions. The formation of the heterogeneous epoxy network and the slowdown of phase separation will prevent a uniform precipitation of the modifier and finally result in a heterogeneous partially phase‐inverted structure or the completely phase‐inverted structure, depending on the amount of modifier incorporated over the critical concentration. © 1993 John Wiley & Sons, Inc.
Azobisisobutyronitrile‐Initiated graft copolymerization of methyl methacrylate onto poly(ethylene terephthalate) fibers
Authors: Saçak Mehmet , Bas̆tuğ Neriman , Talu Muzaffer 
Published: April 2003

AbstractIn this study, the grafting of methyl methacrylate onto poly(ethylene terephthalate) fibers using azobisisobutyronitrile is reported. An increase in temperature and monomer concentration were found to increase the graft yield. The graft yield increased up to an initiator concentration of 0.90 × 10−2 mol/L and decreased at higher initiator concentrations. The fiber densities decreased, and fiber diameters and intrinsic viscosities increased with increasing graft yield. Moisture regain values showed a slight increase with the grafting. Fiber orientation decreased the graft yield to an important extent. The overall activation energy for grafting was calculated to be 11.9 kcal/mol. © 1993 John Wiley & Sons, Inc.
Characterization of friction‐deposited polytetrafluoroethylene transfer films
Authors: Fenwick David , Ihn Kyo Jin , Motamedi Farshad , Wittmann Jean‐Claude , Smith Paul 
Published: April 2003

AbstractThe structure of oriented transfer films of poly(tetrafluoroethylene) (PTFE), previously used as orientation‐inducing layers for a variety of materials, was studied. Transmission electron microscopy and X‐ray diffractometry were empolyed to determine the continuity and relative volume of the PTFE films, which were deposited onto glass substrates by friction transfer at controlled temperatures, pressures, and sliding rates. The thickness and continuity of the films were found to increase with increasing temperature and applied pressure. In the range of sliding rates used (0.1–10 mm/s), no significant correlation between this processing variable and the thickness or continuity was apparent. Transmission electron microscope investigations showed that, generally, the (100) plane of the PTFE crystalline unit cell was parallel to the glass surface. © 1993 John Wiley & Sons, Inc.