bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wood–phenol adhesives prepared from carboxymethylated wood. I
Authors: Shiraishi Nobuo , Kishi Hajime 
Published: April 2003

AbstractPreparation of carboxymethylated wood (CM wood)–phenol resin adhesives has been attempted by two methods, “kneading method” and “solvolysis method,” and their adhesion strength has been studied. The two preparation methods differ in the dissolution step. In the case of the kneading method, CM wood was dissolved in aqueous phenol by kneading at 100–120°C under shear, whereas, in the case of the solvolysis method, the dissolution was facilitated by phenolysis at 80°C in the presence of appropriate amounts of hydrochloric acid. The wood‐based adhesive prepared by the solvolysis method revealed excellent and enhanced applicability compared with that of the adhesive prepared by the kneading method, although the latter can be used as an adhesive for wood. Adhesion strength of these adhesives was enhanced when poorly substituted CM wood and appropriate amounts of formaldehyde were used in the resin preparation. A crosslinking agent for carboxymethyl cellulose, that is, polymeric MDI, was also added just before application. The water‐proof adhesion strength was higher than the JIS specification for phenol resin adhesives for this modification.
In vivo and in vitro blood compatibility of polyelectrolyte complexes formed between cellulose derivatives
Authors: Ito Hiraku , Miyamoto Takeaki , Inagaki Hiroshi , Noishiki Yasuharu , Iwata Hiroo , Matsuda Takehisa 
Published: April 2003

AbstractThe blood compatibility of cellulosic polyelectrolyte complexes (PECs) and the effect of excess charge in PEC on the blood compatibility were examined in detail by both in vivo and in vitro blood tests. For this purpose, two types of quaternary ammonium cellulose derivatives were prepared by treating cellulose or hydroxyethyl cellulose with glycidyl trimethylammonium chloride. In vivo blood tests were made by implanting the polymer‐coated suture into a jugular and femoral vein of a dog. In vitro blood tests include the measurement of whole blood coagulation time on polymer‐coated glass tubes, platelet adhesion measurements using a column packed with polymer‐coated glass beads, and a measurement of activation of the intrinsic coagulation system. It was found that among the PECs examined, the PECs containing quaternary ammonium derivatives as polycation components have an excellent blood compatibility. The experiments on the effect of excess charge in PEC revealed that (i) the relative coagulation time of whole blood is almost independent of the mole ratio of polycation to polyanion component within the mole ratios examined, being in good agreement with those by in vivo blood tests, but (ii) platelet adhesion increases with increasing the mole ratio of polycation/polyanion in the PEC, and (iii) the activation of the intrinsic coagulation system increases with decreasing the mole ratio.
Rheological properties of coatings during drying processes
Authors: Watanabe Koichiro , Amari Takeshi 
Published: April 2003

AbstractCoatings such as paints and printing inks transferred on substrates change from viscous liquids to viscoelastic solids during drying processes and finally become a hardened film. In order to investigate more precisely the viscoelastic properties of coatings during liquid‐to‐solid conversion, we developed the same type of ultrasonic rheometer as employed by Mason et al., in which the reflection coefficient technique is utilized. The complex modulus can be determined by the reflection coefficient and the phase shift. Using this rheometer, we can obtain the viscoelastic properties of coatings at various stages of drying at infinitesimal shear strain at the frequency of 3 MHz.The viscoelastic properties of a commercial offset litho ink which was dried by oxidative polymerization were measured at various temperatures. From the results of viscoelastic measurements, the drying of ink seems to be accelerated remarkably with increasing temperature. As the drying processes progress, a three‐dimensional network structure may be formed in the ink film with the aid of oxidative polymerization. The drying‐time dependence of G′ is different from that of G″. From the drying‐time dependences of G′ and G″, we can quantitatively deduce the internal structure of printing ink films during drying processes and provide a physical explanation for various drying stages. The dispersed pigments in a coating seem to play an important role in film formation and affect the mechanical properties of the drying film.
Effect of cryoground rubber on properties of NR
Authors: Phadke A. A. , Bhowmick A. K. , De S. K. 
Published: April 2003

AbstractThe influence of cryoground rubber (CGR) on the curing characteristics, physical properties, network structure, and failure behavior of natural rubber (NR) has been investigated. CGR was added at two different levels of curatives and in two different ways (i) in powder form and (ii) in mill‐sheeted form (obtained by mechanical treatment of CGR in a two‐roll mill). The form of CGR and level of curatives affect the processing characteristics and technical properties of CGR–NR blends. The acetone extractables in the CGR were found to affect the curing characteristics, but no significant effect on the physical properties was observed. Model mixes were prepared by adding partially vulcanized NR compound in the matrix of the same compound. A three‐layer model was set up to study the diffusion of sulfur from the NR matrix phase to the CGR phase. Scanning electron microscope studies of the fractured surface revealed that the mechanical treatment of CGR effects improved adhesion of CGR to NR matrix and the compatibility between the two phases. CGR acts as an inert filler in NR.
Novel anion exchange membranes having fluorocarbon backbone: Preparation and stability
Authors: Matsui Kiyohide , Tobita Etsuko , Sugimoto Kikuo , Kondo Kiyosi , Seita Toru , Akimoto Akira 
Published: April 2003

AbstractAnion exchange membranes with excellent durability were prepared by chemical modification of Nafion. The modification was achieved by transformation of the sulfonic acid group into quaternary ammonium group. Namely, Nafion membrane was first converted into an amide‐type membrane. Reduction of the carbonxyl group to methylene followed by quaternarization with alkyl iodide resulted in the formation of an anion exchange membrane. The electric resistance of the resulting membranes depends on the equivalent weight of the starting membranes (4.4–6.0 Ω cm2 in 0.5N NaCl). The characteristics of the membranes are the excellent stability toward chemical substances such as organic solvents, oxidizing agents, acids, etc. For example, the membranes are stable in aqueous saturated chlorine solution at 60°C for 1000 hr.
Long‐time sulfenamide‐accelerated sulfur vulcanization of natural rubber/chlorobutyl rubber compounds
Authors: Ducháček Vratislav , Kuta Antonín 
Published: April 2003

AbstractSulfenamide‐accelerated sulfur vulcanization of natural rubber/chlorobutyl rubber compounds has been investigated at temperatures from 155 to 175°C over 0.1 to 400 min. Continuous measurements in a Cone Rheometer were used to estimate the extent of crosslinking, which was plotted against cure time. On the basis of a kinetic analysis, two first‐order vulcanization reactions, crosslinking and degradation, have been evaluated. Over the temperature range studied, there is no significant difference between the values of activation energy for these reactions. The rate of the degradation is slower by a factor of 20 than the rate of crosslinking. The degradation reaction can be limited by increasing the “efficiency” of the vulcanizing system.
Effect of diisocyanate structure on viscoelastic, thermal, mechanical and electrical properties of cast polyurethanes
Authors: Pandya M. V. , Deshpande D. D. , Hundiwale D. G. 
Published: April 2003

AbstractStructure property relationship of four different diisocyanates is studied in detail. The isocyanates selected are TDI, MDI Crude, HDI, and IPDI. Physical properties such as mechanical, dynamic mechanical, electrical, and thermal are studied. Dynamic mechanical analyses are based on the compound resonance principle. Among all, IPDI‐based polymer showed mediocre trend and TDI‐based polymer showed best properties.
Effect of fillers on the compatibility of polymer blends
Authors: Kalfoglou Nikos K. 
Published: April 2003

AbstractThe effects of carbon black, talc, and ultrafine silica filler, at different filler, loading, on the compatibility of two binary blends was examined. These were, the mechanically compatible polyurethane (PU)/poly(vinyl chloride) (PVC) at 25/75 weight ratio, and the poly(ε‐caprolactone) (PCL)/styrene–acylonitrile (SAN) copolymer (with 30% AN content), at the 50/50 blend composition. For the former system, both dynamic mechanical analysis (DMA) and DSC measurements indicated that, depending on the filler surface, boundary layers are formed at the filler–matrix interface shifting the PU relaxation to higher temperatures. No significant effect was observed for the PVC component. Though the mechanical spectra are also affected, essentially no Tg shifts were observed for the PCL–SAN system. A qualitative explanation of selective filler activity towards the blend components was given by invoking the matrix–filler basic–acidic nature. Overall, the fillers had no compatibilizing effect on the blend. Using available theory both DSC and the DMA techniques agree in their estimate of the boundary layer thickness. Moduli data were also analyzed using mechanics models proposed for composite systems.
Determination of residual unsaturation in highly crosslinked, dough‐moulded poly(methyl methacrylate) dental polymers by solid‐state 13C NMR
Authors: Earnshaw Richard G. , Price Carole A. , O'Donnell James H. , Whittaker Andrew K. 
Published: April 2003

AbstractMethyl methacrylate has been copolymerized with eight multifunctional, cross‐linking comonomers in mixtures containing poly(methyl methacrylate) to give highly crosslinked polymers for trial as dental resins. These insoluble, optically opaque polymers have been characterized by solid‐state 13C Nuclear Magnetic Resonance spectroscopy. The crosslinking comonomer could be identified from the appropriate resonances in the solid‐state spectra. Unreacted methacrylate groups could be determined quantitatively from the resonance at 167 ppm due to CO adjacent to CC at concentrations down to at least 0.5% of the total CO. The final conversion of CC double bonds in the comonomer depended on the nature and length of the spacer segment between the reactive methacrylate groups.
Diffusion of an acid dye in nylon—in relation to sorption and diffusion of a gas in glassy polymers
Authors: Sada Eizo , Kumazawa Hidehiro 
Published: April 2003

AbstractThe steady‐state permeation rate data of an acid dye in a nylon film were analyzed via dual‐mode sorption and mobility model based on gradients of concentration. The model used incorporates diffusion in a porelike region, unlike diffusion of a gas in a glassy polymer. There was some possibilities of the Nernst to the Langmuir mode diffusion jump, and the diffusivity was estimated.
Studies on the radiation stability of ion exchange membranes
Authors: Ramachandhran V. , Misra B. M. 
Published: April 2003

AbstractThis article deals with some aspects of γ‐radiation stability of (phenolsulfonic acid, PSA) cation exchange membranes synthesized in the laboratory. The changes in cation exchange capacity, moisture content, coion sorption, concentration potential, area resistance, counterion transference number, and solute flux of the membranes were evaluated before and after irradiation. The membrane samples were irradiated under wet conditions using a 60Co source up to a total dose of 18.65 Mrads. The experimental data point out the possibility of degradation of PSA membranes beyond a dose of 9.78 Mrads, resulting in the loss of functional groups from membrane matrix.
The preparation and properties of acrylic and methacrylic acid grafted cellulose prepared by ceric ion initiation. II. Water retention properties
Authors: Vitta S. B. , Stahel E. P. , Stannett V. T. 
Published: April 2003

AbstractBleached sulfite softwood pulp and the corresponding paper have been grafted with acrylic and methacrylic acids and a number of other monomers. A practical, all aqueous, ceric ion method was used as described in Part I of this series. The water and saline retention values of the grafted pulps were determined. Super water sorbency, up to 48 g/g, were obtained after suitable post treatments. A number of variables were studied including the effects of pH, counterion, crosslinking, drying, and beating. It was gratifying that drying did not affect the effeciency of water or saline water retention. Useful linear functional relationships were found between the saline water retention values and the logarithm of the percent sodium chloride in the water. The two “model” parameters of the plots also correlated well with the water retention values and with the degree of grafting expressed as the ion exchange equivalents of the pulps. The osmotic pressure approach to the water sorption as developed by Grignon and Scallan5 coupled with the restraining forces of the grafted polymer itself is used to interpret the process.
Ionomer/ionomer thermoplastic IPNs based on poly(n‐butyl acrylate) and polystyrene
Authors: Nishiyama Y. , Sperling L. H. 
Published: April 2003

AbstractThermoplastic interpenetrating polymer networks (IPNs) were prepared by combining poly(n‐butyl acrylate) with polystyrene, both polymers crosslinked independently with acrylic acid anhydride (AAA). Decrosslinking of both polymers was carried out by hydrolysis of the anhydride bonds. Neutralization of the carboxylic acid groups to form the ionomer was carried out in a Brabender Plasticorder. Two subclasses of thermoplastic IPNs were studied: (1) Chemically blended thermoplastic IPNs (CBT IPNs) were prepared by synthesizing polymer II in polymer I in a sequential synthesis; (2) mechanically blended thermoplastic IPNs (MBT IPNs) were prepared by melt blending separately synthesized polymers. Rheovibron characterization revealed that of the two combinations, the CBT IPNs were better mixed than the MBT IPNs. Investigations of phase continuity via melt viscosity and modulus suggest that the CBT IPNs have some degree of dual phase continuity. Transmission electron microscopy suggests dual phase continuity and relatively small phase domains, 2000–5000 Å for the CBT IPNs. The mechanical properties from tensile and Izod impact tests showed that the CBT IPNs were stronger than the MBT IPNs.
Addition polyimides. I. Kinetics of cure reaction and thermal decomposition of bismaleimides
Authors: Ninan K. N. , Krishnan K. , Mathew Jainamma 
Published: April 2003

AbstractThe thermal polymerization of four structurally different bismaleimide resins, prepared by reacting maleic anhydride with four aromatic diamines, viz., 4,4′‐diaminodiphenyl methane, 4,4′‐diamino diphenyl ether, 4,4′‐diamino diphenyl sulfone, and 3,3′‐diamino diphenyl sulfone, was followed by differential scanning calorimetry (DSC). The enthalpy change and the kinetic constants for the polymerization reactions were evaluated from the DSC curves. Thermal stability of the cured polymers was studied by thermogravimetry (TG). The kinetic parameters, viz., activation energy E and preexponential factor A, for the thermal decomposition of the cured bismaleimides were calculated from the TG curves using three nonmechanistic integral equations. The kinetic constants (E and A) follow a trend similar to the thermal stability of the polymers.
Characteristics of polymerization‐filled polyethylenes (“Norplastics”) and compositions on the basis of norplastics
Authors: Enikolopian N. S. , Fridman A. A. , Popov W. L. , Stalnova I. O. , Brikenstein A. A. , Rudakov W. M. , Gherasina N. P. , Tchalykh A. E. 
Published: April 2003

AbstractThe peculiarities of a new type of materials—polymerization‐filled polymers (“Norplastics”)—have been studied. Norplastics were tested as polymer fillers. The structure morphological properties of high‐filled polymer composites (HFPC), prepared both with norplastics as fillers and traditional mineral dispersed fillers, have been examined.
Liquid‐rubber‐modified epoxy adhesives cured with dicyandiamide. II.–Morphology and adhesion strengths
Authors: Lee Yu‐Der , Wang Shi‐Kwun , Chin Wei‐Kuo 
Published: April 2003

AbstractThe lap shear and T‐peel strengths of n‐butylacrylate/acrylic acid (nBA/AA)‐copolymer‐modified DGEBA adhesive were evaluated. Adherends used in this study included carbon‐fiber‐reinforced plastics (CFRP), glass‐fiber‐reinforced plastics (GFRP), and aluminum. It was found that the adhesive strengths could be improved by incorporating nBA/AA copolymer in the DGEBA matrix. An optimum functionality of the copolymer existed for maximum lap shear strength. Morphological studies revealed that the adhesive strength was also influenced by the compastibility between the copolymer and the matrix, the property of the adherend as well as the addition of the bisphenol A.
Annealing effects on the crystallinity of polyetheretherketone (PEEK) and its carbon fiber composite
Authors: Ostberg Gunilla M. K. , Seferis James C. 
Published: April 2003

AbstractThe degree of crystallinity of polyetheretherketone (PEEK) has been measured using both the density gradient technique (DGT) and differential scanning calorimetry (DSC). The difference in results between the methods was shown to depend on crystallization taking place during the heating scan in the DSC. By freezing the sample at different stages of the DSC thermogram and measuring its crystallinity in the density gradient column, the existence of induced crystallization for PEEK was established. Though this induced crystallization is not visible in the DSC thermogram, it must be taken into account when comparing the degree of crystallinity measured by the two methods. The induced crystallization was in turn interpreted as a result of an increase in crystal perfection that is also commonly observed during the initial stages of the annealing process. Accordingly, the effect of annealing on the crystallinity was also investigated. DSC scans on annealed samples exhibited a small endothermic peak at approximately 10°C above the annealing temperature. This peak was observed in both neat PEEK and its carbon fiber‐reinforced composite. Annealed PEEK shows, therefore, two melting transitions, a low one which depends on the annealing temperature and a high one which is independent of annealing temperature conditions. Collectively, the results of this study demonstrate that processing conditions and morphological features must be considered in characterizing semicrystalline‐based matrix polymers for high performance composites.
Phase rearrangement in two‐stage emulsion polymers of butyl acrylate and styrene: Mechanical properties
Authors: O'Connor Kevin M. , Tsaur Sheng‐Liang 
Published: April 2003

AbstractThe mechanical and thermal properties of films from a series of two‐stage emulsion polymers were investigated. The emulsion polymers were made by polymerizng styrene in the presence of a preformed poly(butyl acrylate‐co‐divinyl benzene) seed latex. The effects of seed particle size, seed particle crosslinking via the amount of divinyl benzene, styrene/butyl acrylate ratio, and thermal history on the film properties were studied. Latex particles were characterized by light scattering and film formation behavior. Dried films were characterized by differential scanning calorimetry, dynamic mechanical analysis, and stress‐strain behavior. Although evidence was obtained for nearly complete phase separation between the polystyrene (PS) and poly(butyl acrylate) (PBA) phases, the site of styrene polymerization and thus the PS phase morphology is influenced by seed particle size, seed crosslinking, and S/BA ratio. The morphology of as‐dried films consists of finely dispersed PS domains in a continuous PBA matrix. Thermal annealing above the PS Tg causes coalescence of the PS domains, resulting in significantly improved mechanical properties. The extent of PS phase coalescence is also influenced by the level of seed crosslinking.
Radiation‐induced grafting of N,N‐dimethylacrylamide onto polytetrafluoroethylene
Authors: Razzak Mirzan T. , Otsuhata Kazushige , Tabata Yoneho 
Published: April 2003

AbstractGrafting of N,N‐dimethylacrylamide (DMAA) onto polytetrafluoroethylene (PTFE) has been carried out by using gamma rays from a 60Co source. Degree of grafting was affected by grafting conditions. Especially, solvent for the grafting was found to be a very significant parameter to obtain a higher grafting yield. When ethylacetate or acetone was used as the solvent, grafting yield greater than 5% was obtainable while the graftcopolymerization scarcely occurred in the presence of other kinds of solvent such as ethanol or water.Apparent activation energy of the grafting in ethylacetate was calculated to be 7.90 Kcal/mol, and initial grafting rate of it was proportional to 0.55 power of dose rate.
Production and properties of highly oriented polypropylene by die drawing
Authors: Taraiya A. K. , Richardson A. , Ward I. M. 
Published: April 2003

AbstractA comprehensive examination of the die‐drawing behavior of polypropylene has been carried out, examining the effects of draw temperature, haul‐off speed, and initial billet size. A range of oriented products was obtained and characterized, primarily by the determination of Young's modulus at room temperature, the maximum modulus being 20 GPa for a draw ratio RA of 23.2. Using a large‐scale machine, it was found possible to produce drawn products at speeds up to 2 m min−1 at a draw temperature of 155°C and RA of 19.3. The dynamic mechanical behavior of several drawn materials was studied over the temperature range −30 to +80°C. It was of particular interest that the β relaxation was found to be absent in samples of high draw ratio.
Concentrated polymer solution between plates
Authors: Ronca G. 
Published: April 2003

AbstractGeometric requirements, avoidance of boundary conditions, and focus on configurational properties have suggested mean field formulation of the many chain problem using discrete single chain Gaussian partition functions. Mean field account of energetic, combinatorial, and configurational contributions to the free energy provides correct reduction in the limit of remote confinement and avoidance of double counting of interactions. Strong influence of surface adsorption on configurational and global properties of spatial distribution is predicted to occur at lower concentrations. The interplate surface tension has been calculated in decoupled conditions (large separation distances between plates). Numerical results predict an approximate power law dependence of the surface tension on the concentration with exponent ∼ 1.3. Perfectly repulsive boundaries and athermal solvent conditions have been assumed for this calculation.