bluuebunny/crossref_metadata_2025_split huggingface dataset:
Entry pressure and elastic behavior of a branched polyethylene
Authors: Chohan R. K. 
Published: April 2003

AbstractDie entry pressures and elastic parameters derived from these have been determined for one low‐density polyethylene (LDPE) at four temperatures using three dies having different entry angles. The elongational viscosity shows a somewhat different behavior with respect to temperature than the shear viscosity. Mostly the elastic parameters show a temperature‐independent relation to the shear stress but only if the data at the lowest temperature used (130°C) are ignored. The latter data show that the material is much more elastic at this temperature than at higher ones; this is so even when the temperature is increased by only 20°C, after which any further increase gives negligible difference in elasticity. This behavior is probably due to a structural difference which may be a result of increased crosslink sites created by flow‐induced crystallization. © 1995 John Wiley & Sons, Inc.
Reprocessing of liquid‐crystal polymers: Effects on structure and mechanical properties
Authors: Bastida S. , Eguiazábal J. I. , Nazábal J. 
Published: April 2003

AbstractThe effects of reprocessing by successive injection molding cycles on the structure and properties of two thermotropic liquid‐crystal polymers (LCPs), namely Rodrun and Vectra, were analyzed. Reprocessing produces a clear decrease in the melt viscosity of both LCPs. This is attributed to molecular weight decreases as a consequence of chemical reactions. The reactions produced chain scission in both LCPs and new products in the case of Vectra. This gave rise to modifications in the crystalline behavior of Vectra that did not take place in the case of Rodrun. All these facts lead to, with the exception of the modulus of elasticity of Rodrun, an overall decrease in properties, more marked in the case of Vectra. © 1995 John Wiley & Sons, Inc.
Determination of filler content in thermoplastic composites by FTIR analysis
Authors: Fuad M. Y. Ahmad , Yaakob I. , Rusli O. , Ishak Z. A. Mohd , Omar A. K. Mohd 
Published: April 2003

AbstractFTIR quantitative analytical method is described as an alternative technique for computation of the filler content in polypropylene composites. White rice husk ash (WRHA) was incorporated as a filler material into polypropylene homopolymer. Absorption peaks at 480, 621, and 790 cm−1 chosen for the quantitative analysis work have been shown to give good linearity with increasing filler contents. © 1995 John Wiley & Sons, Inc.
Rate of formation of polysulfides of 2‐bisbenzothiazole‐2‐2′‐disulfide in the presence of sulfur and 2‐mercaptobenzothiazole
Authors: Gradwell M. H. S. , Morgan B. , McGill W. J. 
Published: April 2003

Abstract2‐Bisbenzothiazole‐2,2′‐disulfide was heated isothermally with and without sulfur at temperatures between 130 and 178°C for various periods of time and the mixture analyzed by high‐pressure liquid chromatography (HPLC). 2‐Bisbenzothiazole‐2,2′‐monosulfide formed rapidly and 2‐bisbenzothiazole‐2,2′‐polysulfides after an induction period of about 5 min. Polysulfides of higher sulfur rank are formed by the sequential addition of sulfur atoms. 2‐Mercaptobenzothiazole catalyzes the formation of 2‐bisbenzothiazole‐2,2′‐polysulfides and elimates the induction period. Mechanisms for the decomposition of 2‐bisbenzothiazole‐2,2′‐disulfide and the catalytic role of 2‐mercaptobenzothiazole are proposed. © 1995 John Wiley & Sons, Inc.
Deformation behavior of polypropylene/polyamide blends
Authors: Rösch Joachim , Mülhaupt Rolf 
Published: April 2003

AbstractIn recent years, blend technologies have been developed to modify mechanical properties of polypropylene by dispersing discrete stress‐concentrating polyamide microparticles in the continuous polypropylene matrix. The work presented here is concerned with the examination of fundamental relationships between blend morphologies and mechanical properties, especially plastic deformation mechanisms at high strain. Polyamide‐6, polyamide‐12, polyamide‐12 plasticized with N‐butyl‐phenylsulfonamide, and polyamide‐6 in situ embedded in a shell composed of polyamide‐36,6 have been used as blend components in polypropylene blends containing 30 vol % of these polyamides. For modification of interfacial adhesion, maleic‐anhydride‐grafted‐polypropylene has been added. When the yield stresses of polyamide and polypropylene are matched, large elongations at break of the resulting blends can be achieved. The influence of crazing, voiding, and shear yielding has been elucidated by transmission electron microscopic analysis of strained blend samples. © 1995 John Wiley & Sons, Inc.
Properties of biomedical pressure‐sensitive adhesive copolymer films with pendant monosaccharides
Authors: Miyata Takashi , Morizane Mayumi , Nakamae Katsuhiko , Okumura Masakazu , Kinomura Keisuke 
Published: April 2003

AbstractGlucosyloxyethyl methacrylate (GEMA) was copolymerized with butyl acrylate (BA) for the preparation of a biomedical pressure‐sensitive adhesive with pendant monosaccharides, for possible use in medical applications. The measurements of 180° peel strength, ball tack, and holding power for the GEMA–BA copolymer films revealed that the film at the GEMA content of 5 mol % has excellent pressure‐sensitive adhesive properties. Protein adsorption onto the GEMA–BA copolymer film hardly occurred due to very low interfacial free energy between its surface and water. Release profiles of vitamin B12 from the GEMA–BA copolymer film suggests that it is useful as a material for a transdermal therapeutic system. © 1995 John Wiley & Sons, Inc.
Performance improvement of glass‐fiber‐reinforced polystyrene composite using a surface modifier. I. Synthesis and characterization of poly(γ‐MPS‐co‐styrene)
Authors: Jang Jyongsik , Lee Junyeob , Jeong Jongkoo 
Published: April 2003

AbstractPoly(γ‐MPS‐co‐styrene), as a surface modifier of glass‐fiber‐reinforced polystyrene composite, was synthesized to improve the adhesion between glass fiber and polystyrene matrix. The copolymerization was carried out using AIBN as the initiator at 70°C. The reactivity ratios of γ‐MPS and styrene were determined by the Finemann–Ross method. The result was r1 (styrene) = 0.10, r2 (γ‐MPS) = 0.86. Judging from these results, the copolymerization of γ‐MPS and styrene was azeotropic copolymerization and the synthesized copolymer was a random one. Thermal stability of the copolymer was improved as the content of silane in the copolymer was increased and the glass transition temperature decreased. The surface modified glass fiber was investigated with Fourier transform infrared spectroscopy (FTIR). The glass fiber surface was effectively modified with the copolymer. © 1995 John Wiley & Sons, Inc.
Synthesis of reactive oxazolyl styrene–acrylonitrile copolymers
Authors: Hseih D. T. , Schulz D. N. , Peiffer D. G. 
Published: April 2003

AbstractA series of oxazoline‐modified styrene–acrylonitrile (SAN) copolymers was prepared through the reaction of amino alcohols onto preformed SAN copolymers. Consequently, a variety of reactive copolymers were synthesized. The major focus of this study was to examine the influence of reaction conditions, i.e., the nature of the catalyst and amino alcohol structure, on reactivity. The ability to incorporate oxazoline groups onto preformed polymers is dependent on whether homogeneous reaction conditions are met. For example, the use of nonreactive solubilizing agents, i.e., cosolvent, is effective. However, optimum conditions are obtained when the catalyst is completely soluble in the reaction mixture containing the amino alcohol and SAN copolymer. With these restrictions, zinc stearate is quite effective. Our results show that controlled and reproducible levels of oxazoline can be incorporated (typically at a rate of 2 mol %/h) up to high levels. These results are general and therefore are applicable to a wide variety of nitrile‐containing polymers. © 1995 John Wiley & Sons, Inc.
Studies on functionality distribution of extractable sol from HTPB–isocyanate gumstock
Authors: Panicker Sreelatha S. , Ninan K. N. 
Published: April 2003

AbstractHydroxyl‐terminated polybutadiene (HTPB), even when cured with stoichiometric quantities of toluene diisocyanate (TDI), gives some extractable sol from the gumstock and the sol is believed to be predominantly due to the nonfunctional molecules in the HTPB. However, the present work shows that the molecules in the sol contain hydroxyl functional groups whose nature was established by hydrolyzing the urethane present in the sol and by analyzing the functionality distribution of the molecules so generated from the sol. The sol contains chain‐extending difunctional and crosslinking tri‐ and polyfunctional molecules; however, the concentration of the former is more, when compared to the original HTPB. All three types of primary hydroxyl groups of HTPB (G, H, and V) are also present in the sol. While there is a reduction in the G‐type hydroxyl in the sol, there is no major difference in the cis, trans, and vinyl contents of the backbone of the sol and HTPB. The molecules in the sol have been excluded from the crosslinked network, not only because of the lack of their functionality alone, but also as a result of network imperfections which are an integral part of nonlinear polymerization reactions. © 1995 John Wiley & Sons, Inc.
Flow properties at elevated temperatures and clarity of HSPAN gel–water dispersions
Authors: Hardin Richard A. , Burmeister Louis C. 
Published: April 2003

AbstractDispersions of hydrolyzed‐starch–polyacrylonitrile (HSPAN) gel and distilled water underwent permanent diminuntion of room‐temperature viscosity after maintenance above a threshold temperature of 75°C for periods of several weeks. Below the threshold temperature, viscosity measured at room temperature was unaffected. Above the threshold temperature, the final room‐temperature viscosity exponentially varied as the inverse absolute temperature, and the viscosity decreased with increasing temperature. The HSPAN gel–distilled water dispersions exhibited both yield stress and velocity slip at a solid boundary, but the latter was not present at low shearing stresses. The former inhibited natural convection in a vertical slot with an imposed horizontal temperature difference. Clarity of the dispersions was demonstrated by a character‐visibility test. Deaerating the distilled water by boiling before mixing with HSPAN gel improved the clarity of the resulting dispersion by eliminating the formation of bubbles at elevated temperature. © 1995 John Wiley & Sons, Inc.
Extrusion effects on the mechanical properties of Agar
Authors: Rakow Allen L. , Belfiore Laurence A. 
Published: April 2003

AbstractThe mechanical properties of extruded mixtures of Agar and water were measured for two formulations under slightly different extrusion conditions. The extrudate exhibits high tensile strength when moisture content is 30 wt% and very high elongation (> 2000%) when moisture content is 60 wt %. Electron micrographs of extruded samples at these extremes support the mechanical data. © 1995 John Wiley & Sons, Inc.
The surface relaxation of glow discharge‐treated silicone polymer
Authors: Kuznetsov A. Yu. , Bagryansky V. A. , Petrov A. K. 
Published: April 2003

AbstractThe samples of radiationally linked vinyl (1%) methylsilicone elastomer (silicone) were modified in glow‐discharge air plasma. Surface relaxation was studied by the data on equilibrium contact angles. The degree of relaxation is shown to increase with increasing plasma treatment duration, probably due to the increase in the destruction degree of the spatial network of chemical bonds in the silicone surface layer. The changes in the chemical composition of the surface were controlled using attenuated total reflectance‐infrared spectroscopy. Plasma treatment leads to increase of the polar component of the polymer surface energy and increase of the absorption bands of carboxyl and hydroxyl groups in its spectra. These characteristics disappear when the samples are kept in the open air and can be recovered by putting them into water. Such behavior can be explained by the fact that the polar oxygen‐containing groups, forming on the surface due to plasma treatment, pass inside the polymer. Considering the adhesion properties of modified silicone, its biocompatibility was predicted. © 1995 John Wiley & Sons, Inc.
Compatibility in polymer/plasticizer blend system: Thermal, X‐ray, and dynamic mechanical studies of PMMA/PTBF blends
Authors: Kalkar A. K. , Parkhi Purnima S. 
Published: April 2003

AbstractDifferential thermal and dynamic mechanical analysis (DTA and DMA) were carried out on the blend system of atactic poly(methyl methacrylate) (PMMA) with poly(p‐t‐butyl phenol formaldehyde) (PTBF). In both the techniques, the PMMA/PTBF blend system exhibited a composition‐dependent, single glass‐transition temperature, indicating miscibility. The blends exhibited composition‐dependent morphology dominated by induced cluster formation of PMMA as a separate phase in blends. The DTA scans of blens exhibited broad melting endotherms. Also, in DMA, apart from the main relaxation (tan δ), the system showed an additional high‐temperature relaxation (Tu), indicating the presence of a separate phase. In addition, wide‐angle X‐ray diffraction (WAXD), Fourier‐transform infrared (FTIR) spectroscopy, and sonic pulse propagation measurements provide evidence for the formation of PMMA clusters in the bulk PMMA/PTBF blends. The mechanical behavior of the blends is discussed in terms of the variations in shape and magnitude of tan δ, E″, and E″ curves. It is concluded that PTBF acts as a compatible plasticizer in PMMA/PTBF blends and, because of changed morphology, improveds the elongation of blend films compared to pure PMMA. © 1995 John Wiley & Sons, Inc.
On‐line gas chromatography and densimetry to obtain partial conversions of both monomers in emulsion copolymerization
Authors: Noël Lilian F. J. , Brouwer Eric C. P. , Van Herk Alex M. , German Anton L. 
Published: April 2003

AbstractMonitoring and controlling composition drift is an important issue in emulsion copolymerization. Due to the heterogeneity of the polymerization system often combined with nonideal kinetics, predicting copolymer composition and changes in feed composition as a function of time is not straightforward. Therefore, accurate and fast on‐line determination of partial conversions of the separate monomers is a key to understanding and controlling the copolymer system studied. For this reason on‐line densimetry, resulting in overall weight conversion, is combined with on‐line gas chromatography, resulting in the overall ratios of the residual monomer. Combining these two on‐line data gives the partial conversion of each monomer as a function of time without the need of an internal standard. The determination of partial conversion of monomers in batch emulsion copolymerization from on‐line gas chromatography and on‐line densimetry is illustrated for the monomer system methyl acrylate‐vinyl acetate. © 1995 John Wiley & Sons, Inc.
High‐impact poly(ethylene terephthalate) blends
Authors: Penco M. , Pastorino M. A. , Occhiello E. , Garbassi F. , Braglia R. , Giannotta G. 
Published: April 2003

AbstractRubbers of different kind were tested as toughening agents of poly(ethylene terephthalate) (PET), noting significant morphological and mechanical differences. In particular, good results were obtained by using an ethylene–ethyl acrylate–glycidyl methacrylate copolymer. The resulting blend evidenced good particle distribution, and the latter was related to chemical interactions between the rubber epoxy groups and PET terminal groups, including the effect of low molecular weight and polymeric amine catalysts, and to extrusion conditions. © 1995 John Wiley & Sons, Inc.
The synthesis and properties of a cation‐exchange resin prepared by the pyrolysis of starch in the presence of phytic acid
Authors: Lehrfeld Jacob , Baker Frederick L. 
Published: April 2003

AbstractA black charcoal‐like material having cation exchange and adsorption properties was prepared by the controlled pyrolysis of starch in the presence of a commercial phytic acid solution. Resins with binding capacities of 0.7–5.7 meq/g of calcium were prepared by varying the phytic acid to starch ratio, the temperature, or the duration of heating of the reaction mixture. SEM photomicrographs of some of these new materials showed that they are composed of particles similar in size and shape to the starting starch granules. These resins also removed atrazine from aqueous solutions. © 1995 John Wiley & Sons, Inc.This article is a US Government work and , as such, is in the public domain in the United States of America.
Modification of cellulose in conditions of plastic flow under pressure
Authors: Rogovina S. Z. , Zhorin V. A. , Enikolopian N. S. 
Published: April 2003

AbstractThe search for new ecologically pure production processes for numerous cellulose derivatives is important technologically. It is well known that under shear deformation in solid substances, various physical and chemical effects may take place. The possibility of production of some cellulose derivatives, such as carboxymethylcellulose and cellulose acetates, is shown under conditions of joint action of high pressure and shear deformation at room temperature. The formation of an easily hydrolyzed fraction of cellulose under these conditions is also investigated. This reaction procedure is of great practical interest, as it makes it possible to reduce the consumption of reagents and to carry out the process in the absent of solvents. © 1995 John Wiley & Sons, Inc.
Polyacrylamide‐reactive styrene/unsaturated polyester microgel composites
Authors: Ruckenstein E. , Liang L. 
Published: April 2003

AbstractReactive microgels (RM) were prepared by the copolymerization of styrene and an unsaturated polyester in an emulsion of oil (styrene + unsaturated polyester) in water. The adsorption of the unsaturated polyester on the water–oil interface ensured the stability of the emulsion. Furthermore, polyacrylamide (PAAM) crosslinked with RM was obtained by suspending RM particles in an aqueous AAM solution and polymerizing the system at 70°C to obtain a PAAM–RM composite. The extraction experiments of the RM with dioxane and of the PAAM with water indicated the presence of small amounts of soluble PAAM homopolymers and negligible amounts of free RM, the materials being PAAM crosslinked by RM. The extent of swelling of these materials in water decreased with increasing weight ratio of RM/AAM and was independent of the composition of RM. When the final polymerization temperature was increased to 130°C, RM reacted not only with AAM to form a crosslinked polymer, but also with itself to form semi‐interpenetrating reactive polymer networks (SIRPN). The extent of swelling of PAAM–RM SIRPN in water was much lower than that of the PAAM–RM material. Membranes were also prepared by hot pressing at 200°C the PAAM–RM and PAAM–RM SIRPN composites. The swelling behavior of these membranes in water, acetone, tetrahydrofuran, acrylic acid, ethyl alcohol, and dioxane, as well as in the mixtures of ethyl alcohol–water, acetone–water, tetrahydrofuran–water, and acrylic acid–water, was investigated. © 1995 John Wiley & Sons, Inc.
Effects of orientation on the transport of d‐limonene in polypropylene
Authors: Moaddeb M. , Koros W. J. 
Published: April 2003

AbstractKinetics and equilibria of sorption and desorption of d‐limonene in three polypropylene films (unoriented polypropylene [UN], uniaxially oriented polypropylene [UA], and biaxially oriented polypropylene [BA]) were studied at 30°C and various penetrant activities. The weight percent uptake of a saturated vapor of limonene in UN, BA, and UA films ranged ranged from 12.5 to 19.0%. The kinetics of sorption of a saturated vapor of limonene in these polymers exhibits an increasing tendency toward Fickian transport as the degree of orientation increases, with the highly oriented BA approaching a Fickian response. As the penetrant activity is lowered, sorption kinetics tends to show a Fickian response more closely even for the UN and the UA films. Desorption of limonene from the three samples appears to be Fickian and considerably faster than sorption in the initial stages; however, the process decelarates after roughly half of the penetrant has desorbed. Subsequent exposure of the three oriented films to a saturated vapor of limonene resulted in identical sorption kinetics, suggesting the absence of crazing or other irreversible damage often associated with anomalous sorption in glassy polymers. These results illustrate that the concentration dependent anomalies in kinetics of sorption of a large penetrant such as limonene in the unoriented polypropylene film may be influenced by orientation to yield Fickian transport even at the highest external surface concentration. Thus, the orientation processes appear to affect large‐scale swelling‐induced relaxations to a larger degree than it does the diffusional processes which are dependent on smaller‐scale segmental motions. © 1995 John Wiley & Sons, Inc.
Copolymers of higher alkyl methacrylates with triallyl cyanurate
Authors: Ryttel Anna 
Published: April 2003

AbstractCopolymers of higher methacrylates (propyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, and dodecyl) with triallyl cyanurate were synthesized by free‐radical polymerization using benzoyl peroxide as initiator. The properties of the copolymers such as thermal stability, Tg, Vicat softening temperature, hardness, refractive indices nD, chemical stability, density, and shrinkage on polymerization were studied. The influence of the alcohol alkyl chain length in methacrylates and the content triallyl cyanurate in copolymers on their properties is discussed. © 1995 John Wiley & Sons, Inc.
Sequential crystallization kinetics of poly(p‐phenylene sulfide) doped with carbon or graphite particles
Authors: Chen Jen‐M. , Woo E. M. 
Published: April 2003

AbstractIsothermal crystallization kinetics were investigated by differential scanning calorimetry (DSC) for poly(p‐phenylene sulfide) (PPS) doped with amorphous carbon or crystalline graphite particles. Both types of carbon forms have been found to affect the crystallization behavior of PPS to different extents. The crystalline graphite particles have a more pronounced effect on the overall rate as well as mechanisms of PPS crystallization than do the amorphous carbon particles. Relative contributions and competition from crystallizations of two different crystals in the later‐stage crystallization of PPS have been found to cause the phenomenon of deviation from linearity in the Avrami plots. A sequential crystallization model has been shown to describe well the crystallization behavior of the PPS doped with the particles. © 1995 John Wiley & Sons, Inc.
Preparation of glass‐fiber membranes grafted with poly(NIPAAm containing triphenylmethane leucocyanide) and permeation of solutes through the membranes
Authors: Kurihara Seiji , Yoshimura Kazuhiro , Ogata Tomonari , Nonaka Takamasa 
Published: April 2003

AbstractGlass‐fiber membranes (GF membranes) grafted with poly(N‐isopropylacrylamide containing triphenylmethane leucocyanide) [poly(NIPAAm–LeCN)] were prepared. Ultraviolet irradiation of the GF membranes with poly(NIPAAm–LeCN) induced a change in the phase‐transition temperature of the poly(NIPAAm) segments. The changes in both the phase‐transition temperature of the poly(NIPAAm) segments and the permeation rate of solutes are discussed in relation to the dissociation of LeCN molecules. © 1995 John Wiley & Sons, Inc.