bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of poly(phenylene sulfide). I. Studies on the synthesis and the property differences of poly(phenylene sulfide) with terminal chloro groups and poly(phenylene sulfide) with terminal thiohydroxy groups
Authors: Yang Suizhou , Zhang Jinhua , Bo Qingchang , Fang Dongpu 
Published: April 2003

AbstractIn this article, two kinds of poly(phenylene sulfide) (PPS) with terminal groups predominated by chloro and thiohydroxy groups have been synthesized using endcapping by adding monomer. Compared with PPS with terminal thiohydroxy groups, PPS with terminal chloro groups possesses a greater crystallinity, larger crystallite dimensions, a larger particle size, higher thermal stability, and a longer gelation time. © 1993 John Wiley & Sons, Inc.
Anomalous behavior of electrical conductivity of solubilized collagen solutions with thermal denaturation
Authors: Matsushita Satoru , Deki Shigehito , Mizuhata Minoru , Sugita Masami , Kanaji Yukio 
Published: April 2003

AbstractThe temperature dependence of the electrical conductivity, σ, for a collagen solution was measured in the temperature region including the thermal denaturation temperature, td. The σ increased with temperature, t, but decreased at ca. 40°C, and then again increased. In this temperature region, a change of optical rotation, αD, was observed. The change is due to the thermal denaturation. The differential curve of σ vs. t gave clear deflection points and a large peak at ca. 40°C. The td could be estimated from the peak temperature. The td decreased with the increase in the concentration of collagen and with the decrease in the heating rate. These measurements were carried out for the collagen prepared by various methods. Some of them showed one peak; others had two peaks. The td obtained by the measurement of σ correlated with that obtained by the measurement of αD. The activation energy of σ, ΔEa, obtained from the linear relationship between log σ and 1/T, increased with the concentration of collagen, but was unchanged for the heating rate. The ΔEa obtained for various types of collagen showed a constant value. © 1993 John Wiley & Sons, Inc.
A morphological study of HDPE‐blown films using small‐angle X‐ray scattering
Authors: Gupta Anunay , Simpson David M. , Harrison Ian R. 
Published: April 2003

AbstractDiscrete small‐angle X‐ray scattering (SAXS) has been used as an analytical tool to study the development of crystalline morphology in a series of blow‐extruded high‐density polyethylene (HDPE) films. Processing parameters, take‐up ratio (TUR) and blow‐up ratio (BUR), were the primary variables used in this investigation. Results from SAXS have led to the consideration of a new microstructural model for crystallite development in blown films. The model incorporates row‐nucleated lamellae, where crystalline morphology is sensitive to TUR and BUR. Increasing TUR results in an increase in the number of lamellae in a particular stack, a decrease in fluctuations of amorphous and crystalline thickness distributions, a flattening out of undulations of crystal surfaces, and an increase in the lateral dimensions of lamellae. Increasing BUR did not significantly influence any of the SAXS parameters studied; this can be attributed to the low BURs at which the films were made. © 1993 John Wiley & Sons, Inc.
Digestion of crosslinked poly(vinylpyridinium halide) by activated sludge, and application to make poly(methyl methacrylate) biodegradable by incorporation of a pyridinium group into the main chain
Authors: Kawabata Nariyoshi , Uchihori Daisuke , Fukuda Shinji , Funahashi Hirokatsu 
Published: April 2003

AbstractCrosslinked poly(N‐benzyl‐4‐vinyipyridinium bromide) has been found to be digested by activated sludge obtained from sewage works. As an extension of this work, the authors attempted to make poly(methyl methacrylate) biodegradable by incorporation of a pyridinium group. Poly(methyl methacrylate) containing a small amount of N‐benzyl‐4‐vinylpyridinium chloride in the main chain showed remarkable reduction in molecular weight and gravimetric weight when placed in an aeration tank of a sewage works. Molecular weight reduction by activated sludge was more conspicuous when content of the pyridinium group was larger and the original molecular weight before the biological treatment was lower. Since insoluble pyridinium‐type polymer captures microbial cells alive, this biodegradation appears to be facilitated by enhancement of affinity of the synthetic hydrophobic polymer with cells of microogranisms. © 1994 John Wiley & Sons, Inc.
Surface treatment of fluorinated rubber with triazine thiols and their properties
Authors: Mori Kunio , Hirahara Hidetoshi , Oishi Yoshiyuki , Kim Saiso , Tamura Kosaku , Iwabuchi Akira 
Published: April 2003

AbstractFluorinated (FKM) vulcanizates were treated by immersing in an aqueous solution of triazine thiols, NaOH, and onium salts for 15–60 min at 50–95°C (W‐Method). Treated FKM vulcanizates further were postcured in an air oven for 20 h at 200°C to complete the reaction. The onium salt of triazine thiols were found to be formed by a reaction among the triazine thiols, NaOH, and onium salts and to act as cross‐linking agents to the surface of FKM vulcanizates. In the acetone solution of onium salts of triazine thiols, FKM vulcanizates were also treated by immersing for a few minutes at 20°C and then by heating in an air oven for 20 min at 200°C (A‐Method). Triazine thiols were introduced as crosslinks onto the FKM backbone. The degree of cross‐linking in the surface increased by these treatments and the depth of cross‐linking reached up to about 40 μm thickness by control of treating conditions. The coefficient of friction in FKM vulcanizates decreased as a result of the surface treatment up to about 0.5 from 2.6. FKM vulcanizates decreased the tensile strength by these surface treatments because of the generation of cracks on the surface at 50% or 100% elongation. The surface treatment of FKM vulcanizates suppressed markedly the fixing between FKM vulcanizates and stainless steel at 150°C. Especially, the A‐Method was very effective treating for retarding the fixing between FKM vulcanizates and metals. © 1994 John Wiley & Sons, Inc.
Stereocomplex formation between enantiomeric poly(lactic acid). VIII. Complex fibers spun from mixed solution of poly(D‐lactic acid) and poly(L‐lactic acid)
Authors: Tsuji Hideto , Ikada Yoshito , Hyon Suong‐Hyu , Kimura Yoshiharu , Kitao Toshio 
Published: April 2003

AbstractTo obtain poly(lactic acid) (PLA) complex fibers, spinning was performed by wet and dry methods from 5–10 g/dL chloroform solutions of poly(D‐lactic acid) (PDLA) and poly(L‐lactic), both with a viscosity‐average molecular weight of 3 × 105. The dope was extruded from a monohole nozzle into coagulation baths from ethanol and chloroform for wet spinning and into a drying column kept at 60°C for dry spinning. Scanning electron microscopic observation of the as‐spun fibers showed that the surface of the wet‐spun fiber had large basins with diameters of 50–100 μm and many pores with diameters from sub μm to 10 μm, whereas the surface of dry‐spun fiber had a microporous structure with the pore diameter of 1–3 μm. The tensile strength of the wet‐spun complex fiber was very low and could not be drawn at high temperatures, in contrast to the dry‐spun fiber. The tensile strength of dry‐spun complex fiber increased upon hot drawing and showed the tensile strength of 94 kg/mm2 by drawing at 160°C to the draw ratio of 13. Differential scanning calorimetry revealed that the complex fibers contained both the stereocomplex crystallites (racemic crystallites) and the crystallites of the single polymers, PDLA and PLLA, regardless of the spinning methods. The ratio of the racemic crystallites to the single‐polymer crystallites increased with the draw ratio of the complex fiber. © 1994 John Wiley & Sons, Inc.
Blends of metal acetates and polyurethanes containing pyridine groups
Authors: Yang Chang Zheng , Zhang Xiaomang , O'Connell Ellen M. , Goddard Richard J. , Cooper S. L. 
Published: April 2003

AbstractTwo series of segmented polyurethanes based on 3/2/1 and 2/1/1 molar ratios of methylene diphenyldiisocyanate (MDI), N,N‐bis (2‐hydroxyethyl) isonicotinamide (BIN), and poly(tetramethylene oxide) (PTMO, MW = 1000) were synthesized and blended with different metal acetates. The thermal behavior and mechanical properties of the pyridinecontaining polyurethane precursors and their blends were characterized by DSC, DMTA, and tensile testing. The results suggest that coordination between pyridine groups in the hard segments and the metal ions in the acetates improves hard‐domain cohesion and phase separation and, subsequently, has an effect on mechanical properties. The varying ability of the pyridine group to coordinate with different cations results in different extents of phase separation. The interaction of pyridine with Ni or Cu (II) is much stronger than with Zn. It is shown that coordination interactions can be a driving force for phase separation and hard‐domain aggregation in multiblock copolymer systems. Two different morphologies are proposed for polyurethanes of differing stoichiometry to explain the differences in the results from DMTA and tensile testing. © 1994 John Wiley & Sons, Inc.
Thermal behavior of methacrylic acid–ethyl acrylate copolymers
Authors: Bajaj P. , Goyal Meenakshi , Chavan R. B. 
Published: April 2003

AbstractThe thermal degradation behavior of copolymers of methacrylic acid (81.5–17.4 mol%) was studied using thermogravimetry (TGA) and differential scanning calorimetry (DSC) and the degradation products were analyzed using mass spectroscopy and DSC–FTIR. From mass spectroscopy, it was observed that in the copolymers the main degradation products obtained below 280°C included water, ethanol, and methanol, whereas at higher temperature (up to 400°C), CO2, CO, and small olefins were liberated. Elimination of water and ethanol is attributed to anhydride formation, which is believed to result from two routes: (a) anhydride formation involving adjacent acid groups and (b) anhydride formation involving adjacent acid and ester groups. An endothermic transition in the DSC and percent weight loss in the TGA in the same temperature range (140–280°C) support the above proposal. An increase in weight loss with increase in EA content of the copolymer confirms the participation of EA in the anhydride formation. © 1994 John Wiley & Sons, Inc.
A comparison of specular reflection and PA‐FTIR techniques in the analysis of annealed injection‐molded polyamide 6,6
Authors: Jawhari T. , Quintanilla L. , Pastor J. M. 
Published: April 2003

AbstractA comparative study between the specular reflectance and photoacoustic FTIR techniques is presented in this work. The potential and limitations of these two methods are investigated by following and analyzing structural variations that take place at the surface in annealed injection‐molded polyamide 6,6. Both spectroscopic techniques appear to be quite sensitive in detecting small structural changes that occur in polyamide 6,6 when submitted to different annealing temperatures. However, the presence of distorted bands in the specular reflection spectra makes the photoacoustic FTIR method more attractive for the IR vibrational analysis of difficult materials (e.g., composites, black‐filled polymers, paints, etc.) that cannot be easily characterized by conventional transmission FTIR. © 1994 John Wiley & Sons, Inc.
Characterization of diol modified epoxy resins by near‐ and mid‐infrared spectroscopy
Authors: Scherzer T. 
Published: April 2003

AbstractNear‐ and mid‐infrared spectroscopy has been used for the characterization of epoxy networks based on diglycidyl ether of bisphenol‐A cured with linear aliphatic diols of different chain length in the presence of magnesium perchlorate. Absorption bands due to epoxide, hydroxyl, and ether groups were investigated. The intensity of the hydroxyl absorption and the formation of branched and unbranched ether structures in dependence on the molar ratio and the diol chain length are discussed. A mechanism for the network formation process with respect to diol chain length and concentration is proposed: networks with low density are rapidly formed if long diols are used for modification, whereas the incorporation of short diols into the network takes a longer time but yields networks with a higher density. Glass‐transition temperatures of the networks obtained by dynamic thermomechanical analysis confirm the proposed mechanism. © 1994 John Wiley & Sons, Inc.
Composition and temperature effects on air separation through liquid crystalline alkyl cellulose membranes
Authors: Li Xin‐Gui , Huang Mei‐Rong , Lin Gang , Yang Pu‐Chen 
Published: April 2003

AbstractThe air separation through triheptyl cellulose (THC)/ethyl cellulose (EC) blend membranes containing no more than 20 wt % THC at the temperature range from 298 to 358 K was investigated using a variable volume method. The air‐separation ability for the THC/EC membranes were greater than that for the THC‐free pure EC membrane. P for the THC/EC membranes was between 1.06–8.89 × 10−9 cm3 (STP) cm/cm2 s cmHg and P/P 3.04–3.66. The THC/EC membrane showed a unique trend in its P/P − P relationship, i.e., the magnitude of P/P increased simultaneously with that of P. The THC/EC membrane yielded a maximum oxygen concentration in the oxygen‐enriched air (OEA) of 39.5% at an OEA flux of 6.99 × 10−4 cm3 (STP)/s cm2 for a pressure difference of 0.43 MPa at 358 K. After 300 h of measurement at 0.40 MPa and 313 K, the efficiency of the concentrating oxygen was almost constant. © 1994 John Wiley & Sons, Inc.
Preparation and application of low molecular weight poly(vinyl chloride). II. Thermal stability of blended poly(vinyl chloride)
Authors: Yamamoto Kikuo , Maehara Takashi , Mitani Katsuo , Mizutani Yukio 
Published: April 2003

AbstractThe blending effect of poly(vinyl chloride) (PVC) with relatively higher molecular weight (HMW‐PVC) and relatively lower molecular weight (LMW‐PVC) has been investigated by measuring various thermal stability and fusion times. The thermal stability of the blended PVC is improved when the small amount of LMW‐PVC obtained using mercapto compounds as a chain‐transfer agent is blended into PVC with HMW‐PVC. At the LMW‐PVC content from about 5–30 wt %, the thermal stability of the blended PVC is much more improved. Furthermore, the blended PVC with LMW‐PVC, obtained using mercapto compounds, exhibits significant improvement in the discoloration time. The fusion time of the blended PVC is related to the weight‐average polymerization degree of LMW‐PVC and the LMW‐PVC content. © 1994 John Wiley & Sons, Inc.
Molecular weight characterization of fluoropolyoxyalkylenes by gel permeation chromatography
Authors: Gianotti G. , Levi M. , Turri S. 
Published: April 2003

AbstractConditions required for the molecular weight and molecular weight distribution determination of fluoropolyoxyalkylenes by gel permeation chromatography are reported and discussed. Experimental work was carried out with three series of narrow fractions of oligomers having the same perfluorinated copolymeric body and three different types of chain ends. The same calibration curve describes very well the behavior of the three series of samples, so that a “size‐exclusion” mechanism of the molecular separation can be postulated practically. © 1994 John Wiley & Sons, Inc.
Solutions spinning of the high Tc oxide superconductor. II. Effect of organic acid on the complex formation of PVA with the copper (II) ion
Authors: Tomita Hisayo , Goto Tomoko 
Published: April 2003

AbstractAs basic research for the solution spinning of the high Tc oxide superconductor, the effect of organic acid on the complex formation of poly(vinyl alcohol) (PVA) with the copper [Cu(11)] ion was explored with various carboxylic acids, such as formic acid, acetic acid, n‐butylic acid, and lactic acid. The effects of these acids on the interaction between PVA and Cu(II) acetate in aqueous solution were nonexistent, while a chelation of the Cu(II) ion and lactic acid was detected. In the solid state, a linear complex of PVA with the Cu(II) ion was formed by adding organic acid. The ligand of the linear complex was highly dependent on the kind of acid used. © 1994 John Wiley & Sons, Inc.
Syntheses and nonlinear optical properties of polymers prepared from chloromethylstyrene
Authors: Zerroukhi A. , Trouillet A. , Blanc D. , Boinon B. , Cachard A. , Montheard J. P. 
Published: April 2003

AbstractThe synthesis and characterization of new dyes, prepared in two steps from chloromethylstyrene, and containing azo moieties or stilbene are reported. All synthesized monomers show spectroscopic properties (nuclear magnetic resonance, ultravoilet) in accordance with the attempted structure. These monomers have been copolymerized with styrene and the nonlinear optical properties of the new compounds and those of previously described polymeric imines have been studied via second harmonic generation. © 1994 John Wiley & Sons, Inc.
Surface properties and flocculations of globulin‐immobilized fine polymer particles
Authors: Tamai Hisashi , Sakurai Hiroyuki , Suzawa Toshiro , Yasuda Hajime 
Published: April 2003

AbstractCharacteristics of globulin‐immobilized styrene/acrylamide/acrylic acid copolymer [poly(St/AAm/AA)] fine particles and their flocculation by an antigen–antibody reaction were investigated as a function of acrylamide (AAm) content. Immobilization of globulin was carried out through octamethylenediamine with a carbodiimide reaction. The increase in AAm content in particles decreases the amounts of bovine γ‐globulin (BγG) immobilized, shifts the isoelectric points of BγG‐immobilized poly(St/AAm/AA) particles to acidic pH, and increases the dispersion stability of BγG‐immobilized poly(St/AAm/AA) particles. The flocculation rates of antihuman epidermal growth factor (hEGF) immunoglobulin (IgG)‐immobilized poly(St/AAm/AA) fine particles of low AAm content by the antigen‐antibody reaction are higher than that of anti‐hEGF IgG‐adsorbed polystyrene particles, whereas those of high AAm content are lower and decreased with increasing AAm content. © 1994 John Wiley & Sons, Inc.
Fracture mechanics investigation on the PP/EPDM/ionomer ternary blends using j‐integral by locus method
Authors: Ha Chang‐Sik , Kim Youngkyoo , Cho Won‐Jei 
Published: April 2003

AbstractThe fracture mechanics investigation of the polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM)/ionomer ternary blends was performed in terms of the J‐integral by measuring fracture energy via the locus method. Blends were prepared in a laboratory internal mixer. The composition of PP and EPDM was fixed at a 50/50 ratio by weight. Two kinds of Poly(ethylene‐co‐methacrylic acid) (EMA) ionomers were used. The J‐integral value at crack initiation, Jc, of the PP/EPDM/EMA ionomer ternary blends were affected by the cation types (Na+ or Zn2+) and contents (5–20 wt %) of the added EMA ionomers. The ternary blend having 5 wt % of Na‐neutralized ionomer showed a higher Jc value than that of any other ternary blends. The results were discussed with regard to the fracture topology by a scanning electron microscope (SEM). © 1994 John Wiley & Sons, Inc.
The method of measuring macromolecular entanglements of polymers using swelling differential scanning calorimetry (DSC)
Authors: Qin Jian , Hu Panpan , Zhao Jiongxin , Wu Zongquan , Qian Baojun 
Published: April 2003

AbstractSince Bueche, Graessley, Onogi, etc., advanced the concept of macromolecular entanglements, the subject has been studied extensively. So far, there are two kinds of methods of measuring the entanglements in a polymer system: One is the measurement of viscosity or other related properties of polymer fluids, either melts or solutions; the other is the measurement of modulus or other related properties of completely amorphous polymers. Until now, the effective method of measuring macromolecular entanglements for crystalline or semicrystalline polymers and fibers has not been developed. We report here a new method of measuring macromolecular entanglements of polymeric solids—using swelling differential scanning calorimetry (swelling DSC or SDSC), and we prove that the entanglements in fibers and polymeric materials can be measured quickly and conveniently with this method. © 1994 John Wiley & Sons, Inc.
Application of NMR cross‐polarization/modulus correlations to a series of polyurethane elastomers
Authors: Marcinko J. J. , Parker A. A. , Rinaldi P. L. , Ritchey W. M. 
Published: April 2003

AbstractA structure/property relationship is developed between the dynamic storage modulus, E′, and the cross‐polarization time constant TCH for a series of polyurethane elastomers. The correlations made are based on the standard linear solids model (SLSM) and on the concept that TCH is modulated by near static molecular motions. The use of the SLSM to describe the main viscoelastic range of these polyurethanes is contrasted to previous models used to develop similar correlations. © 1994 John Wiley & Sons, Inc.
Graft copolymerization of acrylonitrile onto cotton cellulose by potassium permanganate–thioacetamide redox system
Authors: Eromosele Ighodalo Clement 
Published: April 2003

AbstractThe graft copolymerization of acrylonitrile onto cotton, initiated by the KMnO4–thioacet‐amide redox system in an aqueous medium, has been investigated. The percentage graft yield was determined by varying the concentrations of KMnO4, acrylonitrile, thioacetamide, and temperature. The percentage graft yield increased initially and then decreased with increasing concentrations of KMnO4 and thioacetamide, with an optimum yield not greater than 21%. The percentage graft yield, however, was greatly enhanced with a value of up to 66% as the concentration of acrylonitrile was increased. The percentage graft yield increased with temperature in the range of 35–70°C with a calculated activation energy of 8.33 Kcal/mol. The effects of solvents and amines on the percentage graft yield were also investigated. © 1994 John Wiley & Sons, Inc.
Solubility parameters of poly(4‐substituted α‐acetoxystyrenes) and alternating copolymers of vinylidene cyanide with substituted styrenes
Authors: Belfkira Ahmed , Montheard Jean‐Pierre 
Published: April 2003

AbstractThe δ solubility parameters of three families of polymers have been determined by two calculation methods suggested by Small and Hoy. Hansen's model has also been used to assess δ and its components δd0, δp0, and δh0, so as to obtain more information on the intensity of the forces between the chain segments. Knowing the microstructure, the tacticity, and the thermal behavior of the copolymers has made it possible to explain both the different values of δ and the progression of solubility areas. Using Teas' method has made it possible to visualize on the same map the influence of the forces of interaction. This representation shows that the presence of the vinylidene cyanide unit in styrenic chains implies an increase of δp and a decrease of δd, whereas δh remains roughly constant for the corresponding homopolymer. © 1994 John Wiley & Sons, Inc.