bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between heterogeneous surfaces of polymers and water
Authors: Murase H. , Nanishi K. , Kogure H. , Fujibayashi T. , Tamura K. , Haruta N. 
Published: April 2003

AbstractPreliminary investigations for the interactions between surfaces of polymers and water were conducted by the measurements of contact (θ) and sliding‐angles (α) with water. Work of adhesion (W) and interaction energies were subsequently calculated by using the values of θ and α, respectively. For the evaluation of actual performances of polymeric materials, shear strength of ice adhesion and snow accretion were measured. Characteristics of homogeneous surfaces of polymers in the interaction with water were obtained. On the basis of these concepts, the materials with heterogeneous surfaces were synthesized. Results of surface characterizations in these polymers showed that the relationship between θ and α, and the other surface attributes are very different according to polymer systems. The surface controlled energetically and morphologically, and the superior hydrophobic property prevented the snow accretion, but not ice adhesion. On the other hand, the organopolysiloxane modified with lithium compound provided the lowest strength of ice adhesion, but a poor capability of snow repellency. In the structural and energetic viewpoints', interactions between heterogeneous surfaces and water (snow and ice) were discussed. For the theoretical prediction, the intermolecular energies between model polymers and water were calculated by using a molecular orbital SCF method. The order of interactions calculated were coincident with experimental values deduced from α, but not from θ. The advantage of heterogeneity of surface was supported by the theoretical understanding. © 1994 John Wiley & Sons, Inc.
Characterization and application of crosslinkers for polyurethane aqueous systems: Isopropylidene malonate‐blocked isocyanurate
Authors: Mirčeva A. , Žigon M. , Malavašič T. 
Published: April 2003

AbstractAn adduct of hexamethylene isocyanurate and isopropylidene malonate was prepared and tested as a crosslinker in a one‐pack water‐borne polyurethane system. It was characterized by FTIR, NMR, and SEC; the blocking and curing courses were followed by FTIR and DSC. The crosslinker was a mixture of various oligomers having mainly amide‐type linkages. The cure analysis showed that cleavage of the malonate ring started at around 110°C and was followed by the formation of ester‐type products. After 30 min of heating at 130°C the insoluble part of crosslinked polyurethane films exceeded 80%. © 1994 John Wiley & Sons, Inc.
Environmental stress cracking behavior of short‐chain branch polyethylenes in Igepal solution under a constant load
Authors: Yeh J. T. , Chen Jung‐Horng , Hong Huei‐Song 
Published: April 2003

AbstractAn investigation of the influence of branch length and crystallinity on environmental stress cracking properties of short‐chain branch polyethylenes (SBPEs) in Igepal solution is reported. The precise value of Igepal transition time (ITT) and difference between the failure process of SBPEs in air and in Igepal solution were determined by comparing their plots of notch opening displacements vs. time in air and in Igepal solution. Igepal transition time can only be found as the failure time (tfI) is greater than the critical time Igepal required to “accelerate” the fracture of SBPEs in Igepal solution. Prior to ITT, time dependence of notch opening displacements and fracture surfaces of samples in Igepal solution were similar to those in air. In contrast, obvious voids appeared in the base of craze and crazelike structures containing clear voids were found on the fracture remnants of samples with tfI longer than their ITTs. The value of ITT and tfI were found to increase significantly for samples associated with higher crystallinity. However, no significant difference in value of ITT was found for samples with the same crystallinity, tie‐molecule density, molecular weight, branch frequency, but different branch length. Finally, environmental stress cracking resistance (ESCR) and tfI of SBPEs in Igepal solution increased dramatically as the short‐chain branch length increased. This dramatic improvement in environmental stress cracking properties with short‐chain branch length is attributed to the increasing sliding resistance of the polymer chains through the crystal and through the entanglement in amorphous region at time before and after ITT. © 1994 John Wiley & Sons, Inc.
Electrorheological effect of liquid crystalline polymers
Authors: Inoue A. , Maniwa S. 
Published: April 2003

AbstractLarge increases in shear stress upon application of a 2.0 kV/mm electric field were observed in homogeneous fluids composed of polysiloxane‐based liquid crystalline polymers (LCPs) in dimethyl silicone at a shear rate of 200 s−1. The increase was largest (about 3,000 Pa at 50°C) with LCP consisting of a polysiloxane bearing mesogenic groups as side chains. With LCP having the mesogenic groups within the main chain, the maximum increase was about 1,300 Pa at 90°C. It was about 400 Pa at 30°C with LCP having the mesogenic groups at both ends only (biterminal), and several Pa at 30°C with LCP having the mesogenic group at one end only (monoterminal). The increases were smaller with mesogenic groups of lower positive dielectric anisotropy in the side chain LCP. The side chain, biterminal, and monoterminal LCPs exhibited Newtonian flow in the electric field and shear stress yield at low shear rates in its absence. The complex dynamic modulus and viscosity of the side chain LCP in the electric field showed no dependence on strain at deformation displacements approaching 5°, but in its absence were generally strain‐dependent, and suggest the strong electrorheological effect of these homogeneous LCP fluids is related to a flexible‐chain linkage between their crystalline domains. © 1995 John Wiley & Sons, Inc.
Physical properties of moldings from liquefied wood resins
Authors: Lin Lianzhen , Yoshioka Mariko , Yao Yaoguang , Shiraishi Nobuo 
Published: April 2003

AbstractThe liquefied wood resins obtained by liquefying wood in the presence of phenol using phosphoric acid as a catalyst were applied to prepare the moldings by using hexamine as a hardener. The effects of the molding conditions and the moldings' compositions on flexural properties and water‐sorption kinetics of the moldings were investigated. It was found that the liquefied wood resins had satisfactory and almost uniform curing reactivity, although they were composed of different kinds of wood components. The flexural properties of the liquefied wood moldings were enhanced with an increase in the amount of combined phenol within the liquefied wood and became comparable to those of the commercial novolak when the amounts of combined phenol were larger than 75%. Furthermore, it was also found that with an increase in the content of wood fillers the flexural properties of the liquefied wood moldings were enhanced more effectively than were the cases of the commercial novolak moldings, exhibiting that the liquefied wood resins could gain a greater reinforced effect from compounding with the wood fillers than did the commercial novolak resins, and the greater the amount of combined phenol, the higher the reinforcing performance of wood fillers. In addition, water‐sorption measurements and the SEM observations of the moldings indicated that the liquefied wood resins had much greater hydrophilicity than that of the novolak and revealed a greater compatibility with wood fillers. © 1995 John Wiley & Sons, Inc.
Effect of process conditions on birefringence development in injection‐molded parts. I. Numerical analysis
Authors: Chen Shia Chung , Chen Yung Cheng 
Published: April 2003

AbstractAnalysis of the injection‐molding process based on Leonov viscoelastic fluid model has been employed to study the effects of process conditions on the residual stress and birefringence development in injection‐molded parts during the entire molding process. An integrated formulation was derived and numerically implemented to solve the nonisothermal, compressible, and viscoelastic nature of polymer melt flow. Simulations under process conditions of different melt temperatures, mold temperatures, filling speeds, and packing pressures are performed to predict the birefringence variation in both gapwise and planar direction. It has been found that melt temperature and the associated frozen layer thickness are the dominant factors that determine the birefringence development within the molded part. For a higher mold temperature, melt temperature, and injection speed, the averaged birefringence along gapwise direction is lower. The birefringence also increases significantly with the increased packing pressure especially along gate area. The simulated results show good consistency with those measured experimentally. © 1995 John Wiley & Sons, Inc.
A study on the polymer layer‐forming phenomena in a rotating disk polycondensation reactor
Authors: Cheong Seong Ill , Choi Kyu Yong 
Published: April 2003

AbstractAn experimental study is reported on the measurement of polymer melt film thickness in a rotating disk polycondensation reactor. The layer thickness of molten poly(ethylene terephthalate) on a rotating disk was measured at 280°C using an electrical conductivity probe at different radial and angular positions. It was observed that the polymer film thickness was not uniform in both radial and angular positions, particularly for high molecular weight polymers. For the slowly rotating disk system employed in our experimental study, the disk rotational speed and gravity effects on the polymer‐layer formation were found to be quite significant. The experimental results were used to develop an empirical correlation for the calculation of polymer film thickness and polymer melt holdup on a rotating disk. © 1995 John Wiley & Sons, Inc.
Synthesis of difuran diesters from furfural, and their evaluation as plasticizers for polyvinyl chloride
Authors: Sanderson R. D. , Schneider D. F. , Schreuder I. 
Published: April 2003

AbstractThe compounds 1,1‐bis[5‐(2‐ethylhexyl, 2‐octyl, hexyl, and butyl)carboxylate‐2‐furyl)ethane, and 5,5′‐dihexylcarboxylate‐2,2′ bifuran were synthesized from furfural and characterized for their plasticizing abilities toward polyvinyl chloride (PVC) by dynamic mechanical thermal analyses (DMTA) with di‐(2‐ethylhexyl)phthalate (DOP)as the standard of reference. DMTA gave values for the depression of the glass‐transition temperature (Tg) per mass fraction of plasticizer, and it also yielded a set of parameters, relative to those of DOP, which describe the compatability of the furan diesters with PVC. These values are compared to those of DOP and furan diesters incorporating only one furan ring in the molecular structure, which have previously been tested by this method. The difuran plasticizers are less efficient in lowering Tg than the monofuran plasticizers or DOP, with 1,1‐bis[5‐(2‐octyl)carboxylate‐2‐furyl]ethane the least efficient and 1,1‐bis(5‐hexylcarboxylate‐2‐furyl)ethane the most efficient. On average the compatability toward PVC is better than that of DOP, and similar to that of analogous monofuran structures. © 1995 John Wiley & Sons, Inc.
Rheological behavior of blends of natural rubber and styrene–butadiene rubber latices
Authors: Varkey Jyothi T. , Thomas Sabu , Rao S. Someswara 
Published: April 2003

AbstractThe rheological behavior of blends of natural rubber (NR) and styrene–butadiene rubber (SBR) latices has been studied with reference to the effects of blend ratio, shear rate, surface‐active agents (casein and sodium carboxymethyl cellulose), and temperature. When the SBR content was less than 50%, the viscosities of the blends appeared to be a nonadditive function of the viscosities of the constituent homopolymers; i.e., a positive deviation was observed. This was due to the structural buildup of the SBR domains. The SBR domains underwent agglomeration and consequently so‐called microflocculation took place. The viscosities of all the blends were found to decrease with increase of temperature and shear rate. The increase in temperature and shear rate marginally weakened the structural buildup as evidenced by the lowering of viscosity. As the SBR content in the system increased, the pseudoplasticity of the blend increased. Even in the presence of surface‐active agents the blends showed composition‐dependent positive deviation. However, surface‐active agents marginally reduced the extent of structural buildup by reducing the microflocculation behavior of SBR domains. © 1995 John Wiley & Sons, Inc.
Synthesis of calcium carbonate–chitosan composites via biomimetic processing
Authors: Zhang Sukun , Gonsalves K. E. 
Published: April 2003

AbstractThe crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, at different concentrations of polyacrylic acid (PAA) as an additive. Several techniques have been employed to characterize the systems. The pH of the solution as the one of indices was used to monitor the crystallization. In the absence of polyacrylic acid, the pH of the solution changed from 6.00 to 8.50 during the crystallization; meanwhile, sporadic nucleation and crystallization was observed via optical microscopy. By introducing polyacrylic acid to the systems, positively charged protonated nitrogen and negatively charged carboxylate ions were produced by reaction between the amino group in chitosan and the carboxyl group in polyacrylic acid, which were detected by ATR‐IR and XPS techniques. These charges induced calcium carbonate nucleation of calcite and vaterite crystals on the chitosan‐film surface. The average size of the vaterite phase was about 15 nm, determined by XRD. The pH of the solution changed from 5.80 to 9.25 during the crystallization; moreover, the crystals showed spherical morphology, which consisted of a large number of small particles with a diameter of about 0.2 μm. © 1995 John Wiley & Sons, Inc.
Hydrogenation of 1,3‐butadiene and isoprene prepolymers having carboxyl end groups
Authors: Luo Yanming 
Published: April 2003

AbstractThe hydrogenations of butadiene and isoprene prepolymers having carboxyl and cyano end groups were investigated by two methods: Heterogenous hydrogenations were carried out at 45°C and 50 psi of hydrogen pressure with palladium on carbonate as catalyst. The best degree of saturation and carboxyl retention were 95 and 79% for butadiene prepolymers and 84 and 95% for an isoprene prepolymers, respectively. Dimide reduction was made in xylene at 130–140°C and normal pressure with p‐toluenesulfonylhydrazide (TSH) as the diimide source. A nearly 100% degree of saturation for butadiene prepolymers and 91% for isoprene prepolymers were achieved. The effects of reaction conditions on the degree of saturation and the carboxyl retention, calculation of molecular weight before and after hydrogenation based on H‐NMR spectral data, and diimide reduction with TSH are discussed. © 1995 John Wiley & Sons, Inc.
The effect of transcrystallinity on the transverse mechanical properties of single‐polymer polyethylene composites
Authors: Teishev Albert , Marom Gad 
Published: April 2003

AbstractThe microstructure of polyethylene (PE)/PE composites, consisting of the high‐density PE (HDPE) matrix and ultrahigh molecular‐weight PE (UHMWPE) fibers, was investigated. Single‐fiber composites were prepared and analyzed in a hot‐stage crystallization unit attached to a polarizing microscope, aiming to find out how the conditions of crystallization affected the transcrystallinity (tc) growth at the fiber‐matrix interface. Thermal treatments leading to two extreme microstructures, of either maximum or minimum thickness of the transcrystalline zone, were sought. It was found that a uniform transcrystalline layer was developed on the UHMWPE fiber from the HDPE melt under isothermal conditions, whereas rapid cooling from the melt prevented the generation of tc. The mechanical properties of unidirectional composite laminae either with or without the transcrystalline zone were measured. A comparison of the transverse strength predicted by theoretical models with the experimental values revealed good interfacial adhesion in the PE/PE system. It was shown that the tc growth had a negligible effect on the composite mechanical properties in the longitudinal direction, whereas it resulted in a 50% decrease of the transverse tensile strength and strain to failure. Scanning electron microscopy attributed that observation to premature brittle failure at tc/tc contact regions. © 1995 John Wiley & Sons, Inc.
A macrokinetic approach to crystallization applied to a new thermoplastic polyimide (New TPI) as a model polymer
Authors: Torre Luigi , Maffezzoli Alfonso , Kenny José M. 
Published: April 2003

AbstractThe application of a new macrokinetic approach to polymer crystallization is applied in this work to a new thermoplastic polyimide (New TPI) recently developed as a matrix of advanced polymer matrix composites. The slow crystallization kinetics presented by New TPI in the entire range between the glass‐transition temperature and the melting point makes TPI an excellent model polymer for testing crystallization models. In the approach presented here the variation of the induction time with the temperature is included in the Nakamura model for nonisothermal crystallization, and a simplified expression of the kinetic constant as a function of the temperature is adopted. The proposed model is verified through a comparison with a complete set of experimental data, ranging from the melting point to the glass‐transition temperature of the polymer, obtained in isothermal and nonisothermal conditions. Moreover phase transformation diagrams (TTT and CCT plots) are presented, providing a fundamental tool for understanding the crystallization behavior of semicrystalline matrices and to determine the more appropriate processing conditions. © 1995 John Wiley & Sons, Inc.
Effect of coupling agents on thermal and electrical properties of mica/epoxy composites
Authors: Bajaj Pushpa , Jha N. K. , Kumar Anand 
Published: April 2003

AbstractThe influence of 3‐aminopropyltriethoxysilane, 3‐glycidyloxypropyltrimethoxysilane, and neoalkoxytric(dioctyl pyrophosphato)zirconate on thermal expansion behavior, dielectric strength, and arc resistance of mica/epoxy composites has been investigated. The addition of mica up to 30% resulted in the reduction of thermal expansion with respect to neat resin. However, the coefficient of linear thermal expansion of 30% mica treated with aminosilane was the least among the various coupling agent‐coated filler/epoxy composites. Mica (30%)/epoxy composites showed the highest dielectric strength values (26 kV/mm), but the highest arc resistance was obtained in zirconate‐treated mica (30%)/epoxy composite. © 1995 John Wiley & Sons, Inc.
Modified free‐volume model for pervaporation of water/ethanol mixtures through membranes containing hydrophilic groups or ions
Authors: Kim Hyo Jin , Jo Won Ho , Kang Yong Soo 
Published: April 2003

AbstractThe free‐volume model for pervaporation has been modified by considering the polar path, in order to apply the model to membranes containing hydrophilic groups. The free‐volume parameters were determined by inverse gas chromatography. For the polyacrylonitrile (PAN) membrane, the transport mechanism could be analyzed only by the free‐volume model; however, for a membrane containing a hydrophilic moiety, the transport properties could be interpreted by the modified model. In water/ethanol mixtures, ethanol transports through the membrane matrix, while water permeates through the polar pathways consisting of polar groups or ions and water molecules as well as through the membrane matrix. © 1995 John Wiley & Sons, Inc.
Synthesis and evaluation of some functionalized difuran diesters as plasticizers for PVC
Authors: Sanderson R. D. , Schneider D. F. , Schreuder I. 
Published: April 2003

AbstractButyl, hexyl, and 2‐ethylhexyl diesters of 1,1‐bis(5‐carboxyl‐2‐furyl)‐2,2‐dichloroethene, hexyl and 2‐ethylhexyl diesters of 1,1‐bis(5‐carboxyl‐2‐furyl) ketone, and the hexyl diester of 1,1‐bis(5‐carboxyl‐2‐furyl)methane were synthesized from furfural and evaluated for their plasticizing abilities toward PVC, by the application of dynamic mechanical thermal analysis and [di(2‐ethylhexyl) phthalate] as a standard of reference. © 1995 John Wiley & Sons, Inc.
Permeation of solutes through chemically modified chitosan membranes
Authors: Seo Toshihiro , Ohtake Hitoshi , Unishi Terunobu , Iijima Toshiro 
Published: April 2003

AbstractChemically and mechanically stable chitosan and N‐acylchitosan were prepared. N‐Octanoylchitosan gives the pronounced decrease of water content, whereas N‐benzoylchitosan keeps a higher content of water. The equilibrium sorption of various sodium salts was determined and is explained by a dual mechanism, consisting of partition and Langmuir sorption. The characteristics of the membrances and the size of the salt anions clearly influence permeability as well as sorption. Permeation behavior was interpreted by the Teorell‐Meyer‐Sievers (TMS) theorem. The mobility of anions decreases with Stokes radius, decreasing in the order chitosan > N‐benzoylchitosan > N‐octanoylchitosan, indicating the effect of the polymer chain molecules, especially a steric obstruction effect on the ion transportation through the membranes. The introduction of the N‐acylated hydrophobic group to the charged chitosan membranes appears to enhance permselectivity. © 1995 John Wiley & Sons, Inc.
Analysis and experimental study of gas penetration in a gas‐assisted injection‐molded spiral tube
Authors: Chen S. C. , Hsu K. F. , Hsu K. S. 
Published: April 2003

AbstractCharacteristics of gas penetration and polymer melt flow in gas‐assisted injection molded spiral tubes was investigated by simulations and experiments. Distribution of the skin melt thickness along the gas flow direction was measured, and gas penetration in the primary and secondary stages was identified. An algorithm based on the control‐volume/tiniteelement method combined with a particle‐tracing scheme using a dual‐filling‐parameter technique is utilized to predict the advancements of both melt front and gas from during the molding process. The simulated distribution of gas penetration shows reasonably good coincidence with experimental observations. © 1995 John Wiley & Sons, Inc.
Sorption and interactions of gases in polyaniline powders of different doping levels
Authors: Rebattet L. , Escoubes M. , Genies E. , Pineri M. 
Published: April 2003

AbstractSorption of different gases (N2, O2, CH4, and CO2) were performed on as‐synthesized polyemeraldine base, on HCl 4M doped, on NH4OH 1M undoped, and on HCl 10−2M redoped powders. In the pressure range examined (100–700 torr), linear sorption isotherms were observed for N2 and correspond to an ordinary dissolution in Henry's law state. Concerning O2, CH4, and CO2, nonlinear isotherms were evidenced and could be described by the dualmode sorption mechanism proposed for glassy polymers, which consists of the combination of a Henry's type dissolution with a Langmuir sorption in unrelaxed gaps between macromolecular chains. Specific interactions between polyaniline (PANi) and O2, CH4, and CO2, were studied. Gas permeation experiments were performed by using different upstream pressures, P1, and have confirmed the dissolution of Henry's type for N2 and the dualmode mechanism for O2 and CO2. From the fits of the sorption isotherms, gas solubilities of N2, O2, CH4, and CO2 were calculated for three different gas pressures and analyzed in terms of gas separation for permeation experiments. © 1995 John Wiley & Sons, Inc.