bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on PI/PI adhesion strength
Authors: Wang Tsung‐Hsiung , Ho Syh‐Ming , Chen Han‐Lung , Chen Ker‐Ming , Liang Syh‐Ming , Hung Aina 
Published: April 2003

AbstractThe adhesion of polyimide to polyimide was studied by measuring the peel strength of various polyimide–polyimide composites. Different factors such as diffusion of polyamic acid to polyimide substrate, contact angle, wettability, and the thermal expansion coefficient of polyimide films and the presence of siloxane can affect this adhesion and are discussed in this article. © 1994 John Wiley & Sons, Inc.
Structure–property relationship of HTPB‐based propellants. III. Optimization trials with varying levels of diol–triol contents
Authors: Manjari R. , Pandureng L. P. , Somasundaran U. I. , Sriram T. 
Published: April 2003

AbstractA systematic study has been conducted on a composite solid propellant formulation using hydroxyl‐terminated polybutadiene (HTPB) prepolymer with varying molecular weights and hydroxyl values. Fairly extensive regions of resin parameters have been studied. Contours of important propellant properties have been laid down. In this set of experiments, varying levels of diol and triol contents were used at two different NCO/OH ratios to arrive at the optimum level needed for different grades of HTPB resin. It is seen that different grades of HTPB resin require varying levels of diol–triol contents to give similar properties for the end product. Also, for the best performance, varying the diol–triol ratio at the optimum level of the diol–triol content is necessary. © 1994 John Wiley & Sons, Inc.
Porous polydimethylsiloxane membranes treated with aminopropyltrimethoxysilane
Authors: Kobayashi Takaomi , Saitoh Hitoshi , Fujii Nobuyuki 
Published: April 2003

AbstractPolydimethylsiloxane (PDMS) membranes were made by catalytic hydrosilylation of a siloxane compound having a vinyl group and an SiH group in the presence of 1,4‐dioxane. By washing it with water many pores were formed in the membrane. Then, the pore size of the membrane was controlled by treatment of aminopropyltrimethoxysilane (APTMS) solution. When increasing the APTMS concentration, the pore size of the membrane was reduced by the formation of APTMS oligomer on the surface of the membrane. The characteristics of the membrane was examined by IR, ATR‐IR, and SEM techniques. Also, the permeation properties of dextrans and polystyrene latexes through the treated membrane were examined by the ultrafiltration method. © 1994 John Wiley & Sons, Inc.
Emulsion polymerization of vinyl acetate in a tubular loop reactor
Authors: Iabbadène Akli , Bataille Pierre 
Published: April 2003

AbstractA study was conducted on the emulsion polymerization of vinyl acetate using a loop reactor. Among the variables studied were the agitation, that is, the Reynold's number, and the effect of the presence of silver ions on the reaction rate. The molecular weight and molecular weight distribution of the polymer were determined as well as its particle size. The results are compared with earlier work done in a batch, a continuous tubular, and in a tubular loop reactor. © 1994 John Wiley & Sons, Inc.
Allylamine‐adducted bismaleimide resins. II. Their physical/mechanical properties and morphology
Authors: Lin King‐Fu , Lin Jin‐Sing 
Published: April 2003

AbstractPhysical/mechanical properties of various cured allylamine‐adducted bismaleimides (A‐BMI), such as allylamine‐adducted 4,4′‐bismaleimidodiphenylmethane (A‐BDM), and allylamine‐adducted 4,4′‐bismaleimidodiphenylether (A‐BDE) were investigated and correlated to their morphology. In the previous study, two types of the curing reactions were found one is the homopolymerization through the opening of double bonds in the maleimide groups and the other is the reactions between allyl groups and benzene rings. Dynamic mechanical analysis and scanning electron microscopy of cured A‐BMI indicate that the network produced by homopolymerization is immiscible with that produced by the other reactions. The glass‐transition temperature (Tg) of the former network is lower than that of the latter. In addition, the 50% A‐BDM prepared by reacting BDM with 50 mol % allylamine has the optimal physical/mechanical properties after cure, such as the highest Tg and the highest flexural strength and modulus among the A‐BDM. Moreover, the decomposition temperature of 50% A‐BDM is 450°C, only about 40°C lower than that of the pure BDM. © 1994 John Wiley & Sons, Inc.
IGC study of surface properties of adsorbed styrene/methacrylic acid diblock polymers
Authors: Bosse F. , Eisenberg Adi , Xu Ruijian , Schreiber H. P. 
Published: April 2003

AbstractAn inverse gas chromatographic study has been carried out on a styrene/methacrylic acid diblock polymer adsorbed on particulates of varying acid/base interaction potential. Acid/base interactions between polymer and substrate were shown to result in the selective adsorption of copolymer moieties, leading to interphase surface compositions that varied with thickness. At higher interphase thicknesses, bulk and surface compositions became similar; however, depending on the interaction potential of the adsorbent, the interphase thicknesses at this point varied from 100 to 1000 Å. Adsorbed diblock interphases are to be considered nonisotropic in local composition and molecular conformation. These properties may make possible designing diblock interphases to meet specific compatibilization requirements in polymer composites. © 1994 John Wiley & Sons, Inc.
Cross‐linking of bisepoxide with divalent metal salts of p‐aminobenzoic acid and anhydride
Authors: Takechi Shigetoshi , Matsuda Hideaki 
Published: April 2003

AbstractCross‐linking of bisepoxide with divalent metal salts of p‐aminobenzoic acid and dicarboxylic acid anhydride was investigated. As the bisepoxide, bisphenol A diglycidyl ether was used and hexahydrophthalic anhydride was the anhydride used. As the divalent metal, Mg and Ca were selected. In the cross‐linking reactions, the metal salts showed catalytic activities. In this case, the salt containing Mg exhibited higher catalytic activities than that containing Ca. The cross‐linking reaction was supposed to proceed via a complex mechanism. The cured resins obtained contained amide and ester groups and ionic linkages. As for the physical properties of the novel metal‐containing cured resins, tensile and flexural strengths decreased with an increase in the metal content. However, Rockwell hardness was not affected by the metal content. There was a good correlation between heat distortion temperature and Tg determined by dynamic mechanical properties. Against boiling water, the resins exhibited low weight gain, low change in dimension, and no change in external appearance. In addition, thermal decomposition was accelerated by the incorporated metal. © 1994 John Wiley & Sons, Inc.
Multiphase materials with lignin. XII. Blends of poly(vinyl chloride) with lignin–caprolactone copolymers
Authors: De Oliveira Willer , Glasser Wolfgang G. 
Published: April 2003

AbstractA previously described starlike copolymer consisting of a lignin derivative (hydroxypropyl lignin) and caprolactone has been blended with poly(vinyl chloride) (PVC) over a composition range of 0–100%. Solvent‐cast films of the blends were examined with regard to thermal, mechanical, crystallinity, and morphological characteristics. In addition, the blends were examined with regard to aging effects. The results suggest that the lignin/caprolactone copolymer forms either a miscible (by thermal analysis) or a nearly miscible (with phase dimensions in the order of 10–30 nm) system in which physical properties are modified over a wide range of modulus and elongation. Blends with copolymer content exceeding 50% reveal partial caprolactone crystallinity that increases with age. Lignin derivative not copolymerized with caprolactone, by contrast, produces macrophase‐separated structures with exceedingly poor properties. Lignin caprolactone starlike copolymers are materials ideally suited as plasticizers for PVC. © 1994 John Wiley & Sons, Inc.
Kinetics of poly(acrylic acid) adsorption at the liquid–glass interface
Authors: Bajpai A. K. 
Published: April 2003

AbstractThe kinetic behavior of the adsorption of weak polyacid, namely, poly(acrylic acid) on a smooth glass surface has been studied at 30°C. For the evaluation of various adsorption parameters—the adsorption coefficient, surface coverage (θ), and thickness of the adsorbed layer—a new simple kinetic model has been proposed. The effect of the factors such as pH, electrolyte concentration, and molecular weight on adsorption behavior has been studied. © 1994 John Wiley & Sons, Inc.
Self‐ and mutual‐diffusion coefficients in the dodecane/polystyrene system
Authors: Kim Dukjoon , Caruthers James M. , Peppas Nikolaos A. , von Meerwall Ernst 
Published: April 2003

AbstractThe self‐diffusion coefficient of dodecane in cross‐linked polystyrene was measured using pulsed gradient spin echo nuclear magnetic resonance (PGSE–NMR) spectroscopy. The concentration and temperature dependence of the diffusion coefficient was analyzed by the Fujita and Vrentas–Duda models. Parameters describing the Fujita model were determined from fitting of diffusion data to the PVT behavior of the system. Parameters describing the Vrentas–Duda model were determined from the analysis of the viscosity of dodecane, the viscoelastic relaxation properties, and the glass transition temperature of polystyrene as well as from the diffusion coefficient of the system, measured from independent experiments. Both the Fujita and Vrentas–Duda models described well the concentration and temperature dependence of the diffusion coefficient. Mutual diffusion coefficients were determined from these results. © 1994 John Wiley & Sons, Inc.
Effect of siloxane chain lengths of monomers on characteristics of pervaporation membranes prepared by plasma polymerization
Authors: Matsuyama Hideto , Kariya Ayao , Teramoto Masaaki 
Published: April 2003

AbstractPlasma‐polymerized membranes were prepared from a series of monomers with the different siloxane chain lenghts, i. e., hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane, and effects of the starting monomers on both the structures of the plasma polymers and the pervaporation characteristics of ethanol/water mixture were investigated. By IR and XPS measurements, it was found that with increase of the siloxane chain lenghts of the monomer the siloxane chains in the plasma polymers were linked more continuously and smaller amounts of additional oxygen were newly incorporated into the polymers. All membranes obtained from the three monomers were found to be ethanol‐permselective. From the standpoint of obtaining both high selectivity and high permeation rate, the monomer with the longer siloxane chain was profitable. The relations between the results of the analysis of the plasma polymers by IR and XPS measurements and the pervaporation characteristics obtained are discussed. © 1994 John Wiley & Sons, Inc.
The role of steric effects in the adsorption of chemically similar probes to a poly(methyl methacrylate) surface
Authors: Jacob Pauline , Arola Darren , Berg John 
Published: April 2003

AbstractThe role of steric effects in the adsorption of chemically similar acidic probes to the model basic surface of poly(methyl methacrylate) (PMMA) was examined using the technique of inverse gas chromatography (IGC). The results were expressed in terms of the acid‐base contribution to the Gibbs free‐energy change upon adsorption. The acid‐base component of the adsorption free energy, computed on the basis of theoretical modes of adduct formation, was found to depend strongly on the molecular structure of the adsorbate, suggesting the importance of steric effects. © 1994 John Wiley & Sons, Inc.
Cationic graft copolymerization of tetrahydrofuran onto bromodeoxycellulose
Authors: Aoki Nobuyoshi , Furuhata Ken‐Ichi , Sakamoto Munenori 
Published: April 2003

AbstractCationic graft copolymerization of tetrahydrofuran onto halodeoxycelluloses, which were prepared under homogeneous conditions, was studied with silver tetrafluoroborate as an initiator. 6‐Bromo‐6‐deoxycelluloses gave graft copolymers, insoluble but swollen in tetrahydrofuran, whereas chlorodeoxycelluloses gave no graft copolymer. The graft copolymers were hydrolyzed in 2N HCl to give hydrolyzate solutions and insoluble solids. The hydrolyzate was found to be composed of 6‐O‐(4‐hydroxybutyl) glucose and 6‐O‐(9‐hydroxy‐5‐oxanonyl) glucose as well as oligomers of tetrahydrofuran by gas chromatography and gas chromatography–mass spectrometry after trifluoroacetylation. The insoluble solid was cross‐linked polyoxytetramethylene, which could be hydrolyzed only very slowly in 2N HCl to yield oligomers of tetrahydrofuran. Thermal behavior of the graft copolymer was compared with that of cellulose and of homopolymer of tetrahydrofuran. © 1994 John Wiley & Sons, Inc.
Thermal characteristics of unsaturated dicarboxylic acid durable press finishing systems
Authors: Trask‐Morrell Brenda J. , Choi Hyung‐Min 
Published: April 2003

AbstractThermoanalytical (TA) studies including differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses were carried out to measure characteristics of dried mixtures based on two unsaturated polycarboxylic acids. Model 9% treatment (pad) solutions of maleic (M) and/or itaconic (I) acid, with and without potassium peroxydisulfate (K) as the free‐radical initiator, were prepared with sodium hypophosphite (H) as the catalyst and vacuum oven‐dried. DSC thermograms varied with each component; even the presence of a small amount of component K was evident. TG residue production and maximum rates of weight loss were the most useful thermal parameters. Residue/rate factors, used previously as predictors, were calculated. Previous studies indicated that high residues and low rates were indicators of combinations of reactants that resulted in good durable press treatments for fabrics. Residue/rate factors were used to rank the six mixtures that reflect actual fabric treatment combinations: MH, IH, MIH, and those same three with the initiator present. Rankings indicated that the presence of the initiator significantly increased the residue/rate factor for IHK and for MIHK. The presence of the initiator appears more beneficial to itaconic acid than to maleic acid. The rankings by the TA predictor agreed with textile properties measuring appearance and strength. © 1994 John Wiley & Sons, Inc.
Shear degradation of vinylidene chloride copolymers
Authors: Betso S. R. , Berdasco J. A. , Debney M. F. , Murphy G. L. , Rome N. P. , Richards S. G. , Howell B. A. 
Published: April 2003

AbstractThermally induced dehydrochlorination is a well‐established and prominent degradation mode for vinylidene chloride copolymers. During extrusion, other processes may represent significant degradation pathways. Under shear in air, both oxidative chain‐scission and cross‐linking are prominent processes for both vinylidene chloride/vinyl chloride and vinylidene chloride/methyl acrylate copolymers. Both processes are dependent upon shear rate and temperature. The shear‐stress dependency can be modeled by a kinetic expression that incorporates shear stress into the Arrhenius preexponential factor. Vinylidene chloride/methyl acrylate copolymers appear to be somewhat more susceptible to oxidative chain‐scission than are comparable vinylidene chloride/vinyl chloride copolymers, presumably because of a rapid oxidative attack at exposed methyl acrylate units. Shear‐induced degradation of these materials in air is characterized by early predominant chain‐scission with cross‐linking assuming a greater importance as a function of time. Degradation under shear in a nonoxidative environment is a much simpler process—oxidative chain‐scission is suppressed and cross‐linking is very similar to that observed in air. © 1994 John Wiley & Sons, Inc.
New routes to phenylsilicones
Authors: Stein Judith , Lettko Kevin X. , King Joseph A. , Colborn Robert E. 
Published: April 2003

AbstractTwo alternative nonhalogen routes for the synthesis of phenylsilanes have been explored. In the first method, 2,3‐dimethylbutadiene is reacted with divinyltetramethyldisiloxane via a Diels–Alder reaction. The product can then be aromatized. In the second method, cyclohexadiene undergoes hydrosilylation and the resultant product can be aromatized using palladium on carbon with nitrobenzene as an electron accepter. Phenylsilicones can be prepared in a single step in which a silicone hydride fluid and cyclohexadiene are refluxed in the presence of Pt/C (platinum on carbon) and nitrobenzene. © 1994 John Wiley & Sons, Inc.
A dynamic mechanical study on unidirectional carbon fiber‐reinforced polypropylene composites
Authors: Sengupta P. K. , Mukhopadhyay D. 
Published: April 2003

AbstractFiber‐reinforced polymer composites show high specific strength and stiffness. The alignment of reinforcing fibers results in anisotropy of the material. This anisotropic behavior has been studied through dynamic mechanical analysis of unidirectional carbon fiber‐reinforced polypropylene (CFRPP) composites measured in both parallel and transverse directions to fiber arrangement. Several parameters such as storage modulus (E′), loss modulus (E″), loss factor or damping factor (tan δ), and complex viscosity (MU*) have been determined over a wide range of frequencies and at a fixed temperature. Relaxation and retardation spectra have been constructed for these composites. Modulus enhancement occurs due to stiffness imparted by the fiber and efficient stress transfer at the interface. Relaxation of the polymer matrix ceases with increase in the volume fraction of the fibers. α′‐relaxation is observed for the composite having a 13% volume fraction of fibers and is ascribed to relaxation in the crystalline phase where the additional crystallinity arises out of the transcrystalline growth at the fiber–matrix interface. There exists a good correlation between theroretical curves with the experimental ones. Relaxation and retardation spectra and the dynamic parameters determined for these composites show a good correlation with the volume fraction of fibers as well as the direction of the applied load. © 1994 John Wiley & Sons, Inc.
Silicon‐containing polypyrrolone for gas‐separation application
Authors: Zhou Wenle , Gao Xuesong , Lu Fengcai 
Published: April 2003

AbstractThe permeability to H2, O2, and N2 of silicon‐containing polypyrrolone (SiDA–OTA) and three silicon‐containing polypyrrolone random copolymers was determined at 30°C and 1 atm. The SiDA–OTA shows simultaneously increased permeability and permselectivity over the analogous polyimide (SiDA–ODA). The substitution of SiDA for the BPDA moiety in a polypyrrolone appears to result in a significant increase in gas permeability. The random copolymers contain different amounts of SiDA and DODA, which show lower permeability and higher permeselectivity than does SiDA–OTA. Wide‐angle X‐ray diffraction measurements of the mean intersegmental distance of the materials characterized the packing of different polymer types. © 1994 John Wiley & Sons, Inc.
Continuous UV cure monitoring and dielectric properties of photocross‐linked epoxy–acrylate resins
Authors: Radhakrishnan S. , Pethrick R. A. 
Published: April 2003

AbstractThe changes in viscosity of epoxy–acrylate resins during the photocross‐linking process have been monitored continuously. The curing show change of shape and a distinct peak especially at high intensities. The intensity dependence of gel time follows a superlinear power law of the type tpαI−1.6 rather than the ½ power law. The dielectric relaxation studies on these photocross‐linked films having different compositions of epoxy and n‐butyl methacrylate reveal a particular composition range in which various dielectric parameters pass through critical values. These various findings have been explained on the basis of phase separation taking place during the UV curing process but at a submicron level leading to a very small domain size. © 1994 John Wiley & Sons, Inc.
NG‐migration into double‐base inhibitors. II. Diffusion
Authors: Potgieter H. F. , Sanderson R. D. 
Published: April 2003

AbstractThe maximum sorption of nitroglycerine (NG) in polymeric material was measured in Part 1. The results of the sorption is used to determine the average diffusion coefficient for each polymer, utilizing Fick's second law. These values are compared to the chlorine content in the polymer backbone to ascertain whether the chlorine has any influence in lowering the diffusion coefficient. © 1994 John Wiley & Sons, Inc.
In situ compatibilized polymer blends of phenoxy and ABS
Authors: Chen Sue‐Hua , Chang Feng‐Chih 
Published: April 2003

AbstractThe combination of styrene‐acrylonitrile‐glycidyl methacrylate (SAG) reactive copolymer and sodium lauryl sulfonate catalyst is able to function as an effective in situ compatibilizer for the otherwise immiscible and incompatible polymer blends of phenoxy and acrylonitrile‐butadiene‐styrene (ABS). The copolymer formed from the reaction between phenoxy and SAG under melt blending conditions tends to reduce interfacial tension in the melt and results in finer morphological domains of the blends. The presence of this in situ formed compatibilizer also raises the interphase adhesion of the blends and results in significant improvements in mechanical properties. © 1994 John Wiley & Sons, Inc.
Particle control of Ziegler–Natta catalysts based on TiCl3 for propylene polymerization. Effect of prepolymerization
Authors: Coutinho Fernanda M. B. , Costa Marcos A. S. , Maria Luiz C. Santa , Bruno José C. 
Published: April 2003

AbstractPrepolymerizations employing an extremely high stereospecific and high active catalyst based on TiCl3 modified by di‐n‐butyl ether (DBE) were carried out with different monomers (styrene, propylene, hexene‐1, cyclopentadiene). The influence of prepolymerization on the morphology of polypropylene obtained with TiCl3 catalyst was investigated. The catalyst was synthesized by TiCl4 reduction in toluene solution with A1Et3·DBE complex. The polymer morphology was evaluated through optical and scanning electron microscopies and polymer bulk density and particle size distribution. © 1994 John Wiley & Sons, Inc.
Spontaneous hydrolytic degradability of copolyesters having tetrahydropyran rings in their backbones
Authors: Okada Masahiko , Ito Shinji , Aoi Keigo , Atsumi Miharu 
Published: April 2003

AbstractHomo‐ and copolyesters, containing 2,5‐linked tetrahydropyran rings in their backbones, were prepared by cationic ring‐opening polymerization of bicyclic lactones, 2,6‐dioxabicyclo [2.2.2] octan‐3‐one (1), and its 4‐methoxy‐carbonyl and 4‐methoxy‐carbonyl and 4‐benzyloxycarbonyl derivatives (3 and 4). Copolyesters, having pendant carboxyl groups, were derived from the copolymers containing 4 as one of the comonomers by the catalytic hydrogenolysis of the pendant benzyloxy–carbonyl groups. Copolyesters, containing both 2,5‐linked and 2,6‐linked tetrahydropyran rings in the main chains, were obtained by the copolymerization of 1 with 6,8‐dioxabicyclo [3.2.1] octan‐7‐one (13), which is a structural isomer of 1. Spontaneous hydrolytic degradability of these polyesters was investigated in a phosphate buffer solution (pH 7.5) at 27°C. The degradability of the polyesters markedly depended on the molecular structure: hydrophobic pendant groups retarded the hydrolytic degradation, whereas hydrophilic pendant groups accelerated it. In particular, a small amount of pendant carboxyl groups significantly enhanced the hydrolytic degradability of the copolyesters from 1. Polyesters, containing 2,6‐linked tetrahydropyran rings in their backbones, underwent hydrolytic degradation more readily than those entirely consisting of 2,5‐linked tetrahydropyran rings. © 1994 John Wiley & Sons, Inc.