bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vapor sorption characteristics of condensable hydrocarbon vapor in low‐density polyethylene
Authors: Ghosh S. K. 
Published: April 2003

AbstractSorption characteristics of vapors of pure hydrocarbon and their binary mixtures in low‐density polyethylene were studied under various conditions of temperature and pressure. A new apparatus devised and utilized for the determination of composition of sorbed vapor in case of binary mixtures is described. The study demonstrates the effect of the presence of one component within the polymer on the sorption of another and also the occurrence of selectivity in sorption.
Electrodeposition of polymers from nonaqueous systems. I. Polyimides: Some deposition parameters
Authors: Alvino William M. , Scala Luciano C. 
Published: April 2003

AbstractThe yield and quality of an electrophoretically deposited polyimide are strongly dependent upon a number of parameters that are closely related to the formulation and characteristics of a basic nonaqueous electrophoretic emulsion. Such parameters, which have been optimized for one specific polyimide, are solvent/precipitant ratio, type and concentration of surfactant, emulsion preparation sequence, apparent pH, and solids content.
Particle size dispersion during latex growth
Authors: Cauley Donald A. , Thompson Robert W. 
Published: April 2003

AbstractThe evolution of the latex particle diameter distribution during batch emulsion polymerization is investigated, with emphasis on changes in the breadth of the size distribution. A model utilizing a surface area‐dependent volumetric growth rate of a single particle results in a time‐invariant standard deviation of the size distribution during periods of particle growth only. This behavior is reconciled with some experimental observations by considering the occurrence of particle nucleation during some part of the growth interval. Conclusions based on the results of the model suggest that higher inhibitor and low emulsifier concentrations favor narrow particle size distributions.
Graft copolymerization of methyl methacrylate onto wool in presence of vanadyl sulfate–potassium bromate in aqueous medium
Authors: Subhan Jahanara , Saccubai S. 
Published: April 2003

AbstractGraft copolymerization of methyl methacrylate onto wool was studied in the presence of vanadyl sulfate and potassium bromate. The experimental results suggested that the wool radicals produced in the reaction initated the graft copolymerization and that the graft polymer radicals terminated by mutual combination. An appropriate kinetic scheme was proposed and the rate and energy parameters were evaluated. Alkaline solubility, dye uptake, and tensile strength of the wool samples were determined before and after grafting.
Studies on synthetic‐polymer plates with high surface energy. II. Diethylene glycol bis(allyl carbonate)–unsaturated carboxylic acid system
Authors: Ohtsuka Yasuji , Kaneko Norio 
Published: April 2003

AbstractPolymer plates with high surface energy were prepared by the procedure described in the previous paper, using diethylene glycol bis(allyl carbonate) as a substrate polymer and acrylic acid or methacrylic acid as a hydrophilic monomer. By the alkali treatment (immersing in an aqueous 0.1N NaOH solution for 2 h), the resulting polymer plates had good water wettability (contact angle for water = 10°) and sufficient mar resistance (the scratching hardness = 45–50 g) in a dry state, and their clarities were higher than those for DAP systems previously reported. The surface densities of carboxyl groups on the polymer plate estimated by use of the McBain's equation were 0.18–0.46 molecule/Å2.
Carbanilation of cellulose in the paraformaldehyde–dimethyl sulfoxide solvent system
Authors: Miyagi Yoshifumi , Young Raymond A. 
Published: April 2003

AbstractMethylol cellulos carbanilate (methylol cellulose phenylcarbamate) was prepared under homogeneous conditions with phenylisocyanate following the dissolution of cellulose into the paraformaldehyde–dimethyl sulfoxide system. Previously reported procedures were utilized to control the oligo‐oxymethylene side chain length of the dissolved cellulose. Methylol cellulose carbanilates with different side chain lengths were characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The homogeneous carbanilation reaction was found to be completed with a degree of substitution of around 2.4 within 3 h at room temperature, which is substantially faster than heterogeneous carbanilation. Methylol cellulose carbanilates were found to have lower heats of decomposition (23.5–32.2 kcal/mol, depending upon the side chain length) and lower heats of decomposition temperatures (236°C) under air compared with conventional cellulose carbanilate. This suggests that the decomposition mechanism of the methylol cellulose carbanilate is through decomposition of the oligo‐oxymethylene side chains, while cellulose carbanilate decomposes by rupture of the cellulose carbamate linkage.
Effect of plasma treatments on the steam‐sour gas resistance and lubricity of elastomers
Authors: Arnold C. , Bieg K. W. , Cuthrell R. E. , Nelson G. C. 
Published: April 2003

AbstractElastomers are widely used in drilling and logging applications as static seals such as casing packers and dynamic seals such as o‐rings for drill bits. Static seals often fail in service because of thermochemical degradation due to the combined effects of steam and sour gas at elevated temperatures that are characteristic of deep wells. Dynamic seals frequently fail because of abrasive wear that occurs even at the low temperatures that prevail in shallow wells. We have shown that improved steam–sour gas resistance of a fully formulated ethylene–propylene rubber at elevated temperatures can be achieved by coating the rubber with a thin film of plasma polymerized tetrafluoroethylene. Thus, no change in the mechanical properties of the coated rubber was observed after exposure to steam and sour gas at 275°C for 48 h. In contrast, the shear modulus of the uncoated rubber increased by 96% after the same exposure. While the effectiveness of the fluorocarbon coating decreased at longer exposure times, short‐term protection of elastomers could be beneficial in certain logging operations. It was also found that the coefficient of friction of a nitrile rubber (Buna N) was reduced by 20% after treatment with a carbon tetrafluoride plasma. This enhanced lubricity could lead to better wear characteristics in conventional drill bits where the seal is in contact with a moving metal surface. The surfaces of the plasma treated elastomers were characterized by water contact angle, scanning electron microscopy, and electron spectroscopy for chemical analysis.
High performance electron negative resist, chloromethylated polystyrene. A study on molecular parameters
Authors: Imamura Saburo , Tamamura Toshiaki , Harada Katsuhiro , Sugawara Shungo 
Published: April 2003

AbstractHigh sensitivity and high contrast electron negative resist, chloromethylated polystyrene (CMS) was developed for direct writing electron beam lithography with 1‐μm resolution. The resist shows excellent lithographic performances such as high plasma‐etching durability and negligible “post polymerization effect”. A series of CMS covering a wide range ofM̄w, 6,800–560,000, were synthesized by the chloromethylation of nearly monodisperse polystyrenes. The effects of molecular parameters on sensitivity and resolution were investigated. The chloromethylation remarkably improved the reactivity of polystyrene, but which was saturated above 40% of chloromethylation ratio. About 100 times higher sensitivity could be achieved as compared with the starting material. As the increase of chloromethylation ratio (CR) gradually broadened the molecular weight distribution (MWD), the optimum CR was evaluated to be about 40%. In the above range ofM̄w, the sensitivity varies from 39 to 0.4 μC/cm, whereas the γ‐value varies from 3.0 to 1.4. A sharp edge profile was obtained in developed pattern of CMS resist because of its relatively high glass‐transition temperature (68–115°C) compared with commercial resists and the suitable selection of a developer. The resolution of CMS was compared with the structually related polymers synthesized from polystyrene with a broader MWD or vinylbenzylchloride and poly(chloroethylvinylether) (CEVE). These polymers show significantly lower resolution than CMS, which indicates the importance of MWD andTgin electron negative resist.
Effects of various parameters in differential scanning calorimetry of hydrogen‐peroxide‐treated lignocellulose
Authors: Nguyen Tinh , Zavarin Eugene , Barrall Edward M. 
Published: April 2003

AbstractDifferential scanning calorimetric (DSC) analyses of mixtures of hydrogen peroxide and lignocellulosic materials have been performed. The influence of chamber atmosphere composition, heating rate, pinhole size, lignocellulose particle size, and hydrogen peroxide‐to‐lignocellulose ratio were examined. With the exception of particle size, the variables produced significant effects on the DSC curves. These effects were mainly connected with changes in the atmosphere surrounding the sample, sample density, heat capacity, and heat conductance.
Effects of 6‐anilino‐1,3,5‐triazine‐2,4‐dithiol, zinc stearate, and barium stearate on the thermal stabilization of PVC
Authors: Mori Kunio , Kikuchi Isao , Nakamura Yoshiro 
Published: April 2003

AbstractIndividual action and synergistic effect in the combination of 6‐anilino‐1,3,5‐triazine‐2,4‐dithiol (AF), zinc stearate, and barium stearate on the color stabilization of PVC were investigated. In this system, AF selectively reacts with allylic chlorine atoms in PVC. Consequently, unstable allylic chlorine units were converted to thermally stable allylic structures, thus retarding the development of polyene sequences. Zinc stearate accelerated the reaction of AF with allylic chlorine atoms in PVC, forming the zinc salts of AF (AFZnSt, StC1–H35COO) by reacting with AF. Barium stearate reacted with ZnCl2 which is formed in the above reaction to give St2Zn and BaCl2. Consequently, barium stearate led to the selective reaction of AF with allylic chlorine atoms in PVC and the remarkable retarding effect of discoloration of PVC.
ESR study of radiation‐induced polymerization of styrene adsorbed on silica gel
Authors: Shimada Machiko , Nakamura Yoshio , Kusama Yasuo , Udagawa Akira , Takehisa Masaaki 
Published: April 2003

AbstractThe effect of the specific surface area of silica gels on the radiation‐induced polymerization of styrene adsorbed on silica gel was studied by ESR. The same radicals were generated on the silica gels regardless of the specific surface area, but the stability of the radicals at room temperature depended on the specific surface area. This means that the decay of the radicals proceeded mainly on the surface of the silica gel. Almost all the radicals generated by irradiation were initially in the bulk of the silica gel and migrated from the interior to the surface of the gel. When styrene monomer was adsorbed on the surface of the silica gel, the silica gel radicals interacted with the monomer and initiated polymerization and then generated polymer. The rate of migration of the silica gel radical was rather fast in the case of silica gel with a large specific surface area. Thus, the polymerization behavior of styrene adsorbed on silica gel greatly depended on the specific surface area of the gel.
Surface oxidation of cis–trans polybutadiene
Authors: Smith L. , Doyle C. , Gregonis D. E. , Andrade J. D. 
Published: April 2003

AbstractUncrosslinked cis–trans polybutadiene films were prepared on ultraclean glass microscope slides by uniform dipping. The samples were stored in different environments prior to evaluation of surface oxidation by dynamic contact angle using the Wilhelmy plate method and by X‐ray photoelectron spectroscopy (XPS). Storage conditions evaluated were: (1) laboratory air at 20°C and 30% relative humidity; (2) vacuum at 0.1 torr; (3) distilled water equilibrated with air; and (4) degassed distilled water. XPS and contact angle analysis indicate that samples exposed to air undergo significant surface oxidation within 8 h. Exposure of polybutadiene to air‐equilibrated water results in slower oxidation. Samples stored in degassed water demonstrated less surface oxidation. Vacuum‐stored samples demonstrated the least surface oxidation. Dynamic contact angle measurements demonstrated that receding contact angles are more sensitive to changes in surface oxidation than are advancing contact angles, as expected. Changes in surface wetting characteristics are readily observed after only 1 h in laboratory air, although XPS analysis does not show evidence of oxidation within 4 h of air storage.
Characterization of polymer‐coated optical fibers using a torsion pendulum
Authors: Manzione L. T. , Paek U. C. , Tu C. F. , Gillham J. K. 
Published: April 2003

AbstractA freely oscillating torsion pendulum has been used to characterize the dynamic mechanical behavior of single polymer‐coated optical fibers. The dynamical mechanical spectra of the polymer coatings exhibit a glass transition temperature (Tg), a cryogenic glassy‐state relaxation (Tsec), and another cryogenic relaxation that is attributed to water present in the coating (TH2O). The shear modulus (G′) of the coating was computed from the shear moduli of the composite specimen and the core, assuming that the coating and core deform through the same angle on oscillation. The glassy‐state modulus was the same for both thin and thick coatings, although the intensity of the damping peaks, as measured by the logarithmic decrement, increased with coating thickness. Comparison of the dynamic mechanical behavior of a coated optical fiber and of a free film cast from the same reactive components shows that the polymer itself can absorb water at ambient conditions and display a mechanical relaxation at cryogenic temperatures. The T., H2O and Tsec relaxations are coupled with respect to their intensities. Latent chemical reactivity was found in one coating above its maximum temperature of cure. In this, the temperature of cure determines the glass transition temperature.
Mechanisms of formation of volatile aromatic pyrolyzates from poly(vinyl chloride)
Authors: Lattimer Robert P. , Kroenke William J. 
Published: April 2003

AbstractThe formation of volatile aromatic pyrolyzates in poly(vinyl chloride) has been studied by pyrolysis–gas chromatography–mass spectroscopy. Results from isotopic labeling experiments with perdeutero‐PVC suggest that the aromatic pyrolyzates can be divided into three general classes with respect to their formation mechanisms: (1) intramolecular—benzene and naphthalene are formed almost exclusively via intramolecular cyclization reactions; (2) mixed intra/intermolecular—styrene and indene can be formed either intramolecularly or via transfer of one hydrogen atom between PVC chains; (3) intermolecular—toluene and methylnaphthalene can be formed via transfer of one or two hydrogen atoms between chains. The isotopic distributions observed in the labeling experiments can be reasonably well explained without involving crosslinking (intermolecular CC bond formation) reactions.
High‐temperature redox‐initiated emulsion polymerization of butadiene
Authors: Padwa Allen R. , Paster Mark D. 
Published: April 2003

AbstractThe kinetics of the ferric ethylenediaminetetraacetate (EDTA)–diisopropylbenzene hydroperoxide (DIBHP)‐sodium formaldehyde sulfoxylate (SFS) redox system were determined. The rate constant is a function of the ionic strength μ. A plot of log10 (rate constant), for the rate‐limiting second‐order iron—SFS reaction, vs.μ1/2 has a slope of 1.3 with a limiting rate constant of 295 ± 15 L. mol−1. min−1 at μ = 0. The slope of this plot decreases to essentially zero for μ > 0.06M. Incorporation of these results into the Smith‐Ewart model for emulsion polymerization correctly predicts the dependence of latex particle size on Fe and DIBHP concentration, but a much lower dependence on SFS concentration is observed.
Interaction of polymerization conditions, structural variables, and mechanical properties of rubber‐modified plastics produced from bulk polymerized styrene/poly(butadiene‐co‐styrene)
Authors: Mui Ernie Tak Cheung , Boateng Victor Berko , Fellers John F. , White James L. 
Published: April 2003

AbstractRubber‐modified polystyrenes were prepared by bulk polymerization with seven different butadiene–styrene copolymers of differing chemical microstructures. The products were structurally characterized through measurement of the swell ratio, percent insolubles, intrinsic viscosity of the soluble fraction, and transmission electron microscope photomicrographs. Increasing initiator concentration or raising polymerization temperature gives lower molecular weight, higher rubber crosslink density, and decreased grafting. Increasing rubber content generally leads to aggregation. Tensile stress–strain curves and Izod impact strengths were measured. High Izod impact strength and increased elongation to break are favored by increasing matrix molecular weight, rubber content, and extent of grafting.
Characterization of cotton–polystyrene graft copolymers
Authors: Thejappa N. , Pandey S. N. 
Published: April 2003

AbstractCharacterization of cotton–polystyrene graft copolymers prepared by ceric ion initiation is reported. Various techniques studied include moisture sorption, solubility in cupriethylenediamine (CED), infrared spectra, differential thermal analysis (DTA), electron micrographs and X‐ray diffractograms, which point to the existence of true grafting. The graft copolymers showed a slight fall in breaking load and improved resistance to wetting.
Utilization of waste cellulose. IV. Comparative study of the reactivity of different substrates in the enzymatic hydrolysis with trichoderma viride
Authors: David C. , Thirỳ P. 
Published: April 2003

AbstractDifferent cellulosic substrates are compared. Cellulose II (grinded Cellophane®) was demonstrated to be a very reactive substrate without any other pretreatment. Indeed, Cellophane®, even coated one side with PVDC or nitrocellulose, can be hydrolyzed to a very high yield of glucose in a reasonable time. Suspensions with an initial high content of substrate can be used. Different pretreatment (ball milling, γ‐irradiation, and Fe2+/H2O2) were found to modify the reactivity of cellulose I. The pretreatments which result in the chemical transformation of the glucose units of the initial cellulosic substrate are shown to inhibit the enzymatic hydrolysis.
Graft copolymerization of methyl methacrylate (MMA) onto silk using potassium peroxydiphosphate–cysteine (PP–Cys) redox system
Authors: Mishra Munmaya K. 
Published: April 2003

AbstractPoly(methyl methacrylate) has been grafted onto mulberry silk in an aqueous medium by using potassium peroxydiphosphate–cysteine (PP–Cys) redox initiator. Various effects upon grafting such as concentration of cysteine, concentration of peroxydiphosphate, concentration of monomer, concentration of sulfuric acid, and temperature were studied. At a low range of cysteine concentration (6.25 × 10−4 mol/L), the rate of polymerization Rp (%/s) is proportional to cysteine concentration and the exponent is calculated to be 0.8. The monomer exponent is calculated to be unity up to the concentration of 65.72 × 10−2 mol/L. From the Arrhenius plot of log Rp vs. 1/T (T = absolute temperature) the overall activation energy is computed to be 15.19 kcal/mol. A suitable kinetic path has been pictured and a rate expression has been derived.
The dissolution of cellulose in anhydrous chloral/aprotic solvents
Authors: El‐Kafrawy Adel , Turbak Albin F. 
Published: April 2003

AbstractTwo new approaches toward the chemical modification and rapid dissolution of cellulose pulp in aprotic solvents containing chloral are presented. In the first method, cellulose pulp is water activated and then solvent exchanged prior to the addition of chloral. In the second method, cellulose pulp is heated in refluxing solvent and then cooled to ambient temperature before the addition of chloral. The methods do not entail the use of catalysts but require the preactivation of the pulp prior to treatment with chloral. Clear solutions obtained by the water activation–solvent exchange method were cast into films, and after washing with water the product was soluble in a variety of organic solvents including acetone. IR and NMR (1H and 13C) analyses as well as chemical analyses led to the conclusion that a cellulose chloral hemiacetal with a DS of 2.2 is initially formed which then slowly decomposes upon standing at 23°C to a relatively stable hemiacetal of DS 0.4. Complete regeneration to cellulose results upon standing for an extended period or treatment with 1 N acetic acid at 80°C, 1 N HCl at 50°C, 0.5% NH4OH or 0.1 N NaOH at 23°C. When solutions, obtained by the hot solvent activation method, were coagulated in water at ambient temperature, regenerated cellulose was obtained. In both methods, little or no degradation of the regenerated cellulose resulted.
Photodegradable polymers: Poly(arylene keto amine)s
Authors: Huang Samuel J. , Byrne Catherine A. 
Published: April 2003

AbstractLow‐molecular‐weight poly(arylene keto amines) were prepared from the polymerization of 4,4‐bis(chloroacetyl)diphenyl ether, 4, 4′‐bis(bromoacetyl) diphenyl ether, and 4,4′‐bis(2‐bromopropionyl) diphenyl ether with piperazine, 4, 4′‐trimethylenedipiperidine, and N, N′‐dimethyl‐1,3‐propanediamine. These film‐forming polymers and suitable monomeric model compounds were found to be degraded by photolysis. The poly(keto amines) resisted degradation by the fungi As‐pergillus niger and Aspergillus flavus.
Effect of pH on the rate of emulsion polymerization of styrene initiated by potassium persulfate
Authors: Rahman A. , Brown C. W. 
Published: April 2003

AbstractThe influence of pH on the emulsifier property (micellar molecular weight) of sodium dodecyl sulfate has been studied in conjunction with the effect of pH on the rate of emulsion polymerization of styrene initiated by potassium persulfate. The rate of polymerization was found to be pH dependent. The micellar weight of sodium dodecyl sulfate has been determined at various pH values. The miceller weight was found to increase with decrease in pH. On the basis of the result, a suggestion was made that the effect of pH on micellar molecular weight can account for the observed behavior of the rate of polymerization.
Cationic oligomerization of 1‐hexene catalyzed by EtAlCl2–chloroacetic acid complexes
Authors: Higashimura Toshinobu , Miyoshi Yoshihiro , Hasegawa Hiroshi 
Published: April 2003

AbstractLower oligomers (dimer to tetramer) of 1‐hexene were obtained in high yield (65 wt %) with a new cationic complex catalyst, EtAlCl2CCl3CO2H, in n‐hexane at 70°C, trimer being the major product. A strong oxo acid, CF3SO3H, yielded very similar products under the same conditions. Characteristics of the 1‐hexene oligomerization by these two catalysts were the high selectivity for dimers to tetramers and the absence of cracking of the product. In contrast, EtAlCl2 or AlCl3 alone led to oligomers with a higher molecular weight (∼103) and a broad molecular weight distribution, the structure of which was very complicated because of extensive cracking of products. A series of EtAlCl2chloroacetic acid (CClnH3–nCO2H, n = 0–3) complexes were also examined as catalysts. The yield of dimer to tetramer increased with increasing acidity of the chloroacetic acids. The mechanism of the 1‐hexene oligomerization with these complex catalysts was discussed on the basis of the structure of product oligomers.
Structural considerations in case II swelling of crystalline poly(ethylene terephthalate)
Authors: Haga Toshio 
Published: April 2003

AbstractThe Case II swelling in chloroform was discussed with regard to the fine structure for the crystalline PET. The case II swelling was associated with the character of the crystallites. It was inferred that the fine structure related to the Case II behavior was effectively plasticized during the swelling process.