bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheological and extrusion characteristics of glass fiber‐reinforced polycarbonate
Authors: Knutsson B. Anders , White James L. , Abbas Kent B. 
Published: April 2003

AbstractAn experimental investigation of the rheological properties of glass fiber‐reinforced polycarbonate melts and the extrusion of such compounds through capillary and slit dies is presented. The viscosity–shear rate function seems independent of instrument for cone‐plate and capillary investigations. The presence of fibers increases the level of the viscosity. Normal stresses at fixed shear stress are also increased by the presence of fibers. The extrudate swell is decreased by the presence of fibers and surface roughness is increased. Fiber orientation increases and surface roughness decreases with increasing extrusion rate.
Inhibition of photoinitiated degradation of polycarbonate by cerium (III) overcoating
Authors: Klein Andrew J. , Yu Hyuk , Yen William M. 
Published: April 2003

AbstractPhotodownconversion of UV radiation incident on a polymeric substrate, polycarbonate, into visible and IR region is effected by coating the substrate with cerous chloride (CeCl3)/poly(vinyl alcohol) complex whereby photolytic degradation of the substrate is significantly inhibited. Thus it appears that cerous ion coating serves as an effective UV screener. The testing method consists of exposing the coated and naked substrate films to a medium intensity UV source with a cutoff filter below 280 nm for different intervals and determining their optical transmission characteristics. Some of the cerous ion coated films were further overcoated with polyvinyl acetate in order to prevent ion leaching by water. The final product retains the visible and IR transmittance of untreated polycarbonate film, and when the optimum composition of CeCl3 in poly(vinyl alcohol) is coated, its transmission spectrum is barely changed even after 24 hr of UV irradiation. The object is to develop inexpensive solar glazing materials which can last up to 20 years without deterioration of their optical and mechanical properties upon solar irradiation.
Phase separation behavior of rubber‐modified epoxies
Authors: Wang T. T. , Zupko H. M. 
Published: April 2003

AbstractThe compatibility and phase separation behavior of mixtures of the diglycidyl ether of bisphenol A and carboxyl‐terminated butadiene‐acrylonitrile copolymers were studied by means of light transmission, viscosity measurements, and optical microscopy. Cloud point measurements of the blends prior to curing showed a strong influence of acrylonitrile on the miscibility behavior, especially near the critical composition of the system. In addition, the cloud point curves showed a highly skewed shape which turned out to be particularly favorable to the formation of a rigid but tough two‐phase structure. Blends subjected to isothermal cure at 120°C were found to begin phase separation at a progressively shorter time with increase in the copolymer content. Furthermore, while the phase domains tended to cease growing at the time of gelation, the composition within the sample continued to change well beyond the gel point.
Studies on synthetic polymer plates with high surface energy. I. Diallyl phthalate‐unsaturated carboxylic acid system
Authors: Ohtsuka Yasuji , Kaneko Norio , Takami Fumio 
Published: April 2003

AbstractA new preparation technique of the polymer plate with high water wettability and sufficient mar resistance was proposed. The gel plate resulting from the prepolymerization of diallyl compound (M1), diallyl phthalate (DAP), in a casting cell was immersed in an aqueous solution of unsaturated carboxylic acid (M2), acrylic acid (AA), and methacrylic acid (MAA), at a specific temperature for a specific time. M2 was copolymerized with the remaining M1 in the region near the surface of the gel plate, and polymer plates with the following characteristics were obtained: for DAP–AA system, θi (contact angle of the alkali‐treated plate) = 10.5° and mar resistance (for the alkali‐treated plate at a dry state) = 70 g; for DAP–MAA system, θi = 8.3°, and mar resistance = 65 g.
Grafting vinyl monomers into nylon‐6. II. Graft copolymerization of methyl methacrylate onto nylon‐6 by hexavalent chromium ion
Authors: Nayak Padma L. , Lenka Subasini , Mishra Munmaya K. , Tripathy Atanu K. 
Published: April 2003

AbstractThe feasibility of chromium(VI) to induce graft copolymerization of methyl methacrylate onto nylon‐6 was investigated in the presence of nitrogen. The rate of grafting was determined by varying monomer concentration, chromium(VI) concentration, temperature, acidity of the medium, solvents, inorganic salts, and redox system. The graft yield increases significantly by increasing the monomer concentration. The graft yield increases with increase of [Cr(VI)] up to 0.025 mole/liter. With further increase of [Cr(VI)], the graft yield decreases. The increase of acid concentration up to 0.395 mole/liter results the increase in graft yield. Beyond this concentration the graft yield decreases. The graft yield increases with increase in temperature up to 55°C and thereafter it decreases. The graft yield is medium dependent. The graft yield increases with increasing thiourea concentration upto 0.0025 mole/liter but beyond this concentration, the percentage graft yield decreases. A suitable kinetic scheme has been proposed and the rate equation has been evaluated.
Spontaneous ignition of styrene‐butadiene rubber
Authors: Emmons Howard W. 
Published: April 2003

AbstractLaboratory experiments with small samples of styrene‐butadiene rubber show a complex thermal history which suggests the presence of both endothermic and exothermic processes. The suggested mechanisms are shown to be qualitatively correct by computer simulation. Both the laboratory tests and two larger scale tests show that styrene‐butadiene rubber of the present composition will not spontaneously ignite if its surroundings are held at a sufficiently low temperature below about 220°C (428°F).
Thermally stimulated depolarization current studies on strain‐induced relaxations in polymers
Authors: Hong Jauwhei , Brittain J. O. 
Published: April 2003

AbstractThermally stimulated depolarization current (TSD) method has been used to study the molecular relaxation from room temperature up to the glass‐transition temperature for three plastically deformed polymers. A well‐defined distinct α′ peak has been observed in the vicinity of 70°C for polycarbonate, polysulfone, as well as poly(ethylene terephthalate), that had been annealed above Tg and subsequently cold‐rolled. Since this relaxation is not observed after the initial measurements, it is a nonequilibrium relaxation. In the case of polycarbonate, the nonreversible α′ process had an activation energy ranging from 1.22 to 1.75 eV and an intensity proportional to the degree of deformation resulting from cold‐rolling. The spontaneous polarization in the rolled material was believed to originate from the initial anisotropy which was subsequently enhanced by the rolling process. Density measurements, as well as the birefringence observation, have been performed on the rolled specimens. All the studies led to the conclusion that the molecular motion responsible for this α′ peak was the disorientation of local chain segments from their aligned conformation frozen in during the cold‐work.
Dual permeation of acid dyes through nylon 6 membrane
Authors: Tak Tae‐Moon , Sasaki Tamotsu , Komiyama Jiro , Iijima Toshiro 
Published: April 2003

AbstractPermeation of acid dyes in nylon 6 membrane was measured and analyzed by the dual sorption and diffusion mechanism, comprising partition and Langmuir‐type modes. The results were compared with our previous work on diffusion in the same system by the film roll method. Diffusion coefficients of both dye species were found to be similar in magnitude.
Thermal properties of photo‐oxidized nylon 6 fibers
Authors: Fujiwara Yasuharu , Zeronian S. Haig 
Published: April 2003

AbstractNylon 6 fiber begins to increase in weight at about 180°C when heated in oxygen. The increase is attributed to an uptake of oxygen resulting from thermal oxidation. A similar weight increase is not found in photo‐oxidized nylon 6 on heating in oxygen. It appears that nylon 6 tends to form volatile compounds more easily on heating after photodegradation. Changes detected by differential thermal analysis and also by thermomechanical analysis after nylon 6 has been exposed to sunlight are discussed primarily in terms of the supramolecular structure of the fiber.
Cresylic soluble polyimides
Authors: Sheffer Howard 
Published: April 2003

AbstractPolyimides are prepared by reaction of dianhydrides with aromatic diamines under dehydrating conditions to insure conversion of the polyamic acids to polyimides. Cresylic acid solubility is observed only for cyclopentane dianhydride and benzophenone dianhydride. Most of the batches are made from BPDA, since it is the preferred dianhydride for thermal stability. Of 19 aromatic diamines only 2,4‐ and 2,6‐diaminotoluene, 2,4‐diaminoanisole, 4,5‐dimethyl‐1,2‐phenylene diamine and 1,5‐diamino‐4,8‐dihydroxyanthraquinone contribute a great deal toward making soluble polyimides of BPDA. 2,4‐Diamino‐acetanilide when used as the only diamine also gives a soluble polyimide with BPDA. The solubility of polyimides can be correlated with their solubility parameters, their symmetry, and their tendency to hydrogen bond.
Effect of a methyl substituent in the polymerization–crosslinking treatment of cotton with NMMA and NMA
Authors: Shih Frederick F. , Rowland Stanley P. 
Published: April 2003

AbstractAn estimation of structures of reagent residues in cotton fabrics treated with N‐methylolmethacrylamide (NMMA) and N‐methylolacrylamide (NMA) and comparison of textile performance of the NMMA–cotton and NMA–cotton provide the basis for insight into the structure–performance relationship in these fabrics. The α‐methyl substituent, which constitutes the difference between NMMA and NMA, accounts for an altered composition of reagent residues in the treated cotton. The more attractive balance of strength–abrasion resistance with resilience for the NMMA–cotton seems to be a result of a lower degree of covalent crosslinking, which appears compensated by a higher elastic modulus in the NMMA network polymer.
Sulfonation studies of copolymers, graft copolymers, and polymeric gels using phase transfer catalysts
Authors: Paul Swaraj , Rånby Bengt 
Published: April 2003

AbstractA new sulfonation method using phase transfer catalysts was applied to sulfonate a number of polymer matrices in an aqueous two‐phase system. The polymer matrices included in this study are (1) styrene (Sty) and acrylonitrile (AN) copolymers with glycidyl methacrylate (GMA), (2) graft copolymers of cellulose with GMA, and (3) polystyrene and polyacrylate gels containing GMA as comonomer. The presence of polar groups such as AN in the polymer matrix makes the sulfonation easier. For cellulose graft copolymers, the extent of sulfonation was not much affected by the phase transfer catalysts, presumably due to the high polarity and high water uptake capacity of the cellulose base. For other polymer gels, the following factors influence the extent of sulfonation: (1) the method of gel synthesis, i.e., gels synthesized by delayed addition of GMA give a higher degree of sulfonation; (2) the nature of the crosslinking agent, i.e., gels with ethylene glycol diacrylate (EGDA) gives a higher degree of sulfonation than gels with divinylbenzene (DVB); (3) the pore size of the gels, i.e., gels with larger pore sizes gave higher degree of sulfonation; (4) increasing polarity of the backbone structure of gels favors increased sulfonation, e.g., MMA–GMA–EGDA gels give 54% sulfonation, whereas Sty–GME–EGDA gives only 38%.
Novel oxidatively drying urea resin. II. Surface coating properties of N,N′‐bis(methoxymethyl) urea‐based air‐drying resins
Authors: Toivonen Hannu 
Published: April 2003

AbstractThe surface coating properties of the air‐drying urea resins prepared by polycondensating N,N′‐bis(methoxymethyl) urea (BMMU) with trimethylolpropane diallylether (TMPDA) and 2‐ethylhexanol (2EH) were studied. It was found that the thinnability of the ethanolic resin solutions with water decreased with increasing molecular weight and the degree of modification of the resins with TMPDA and 2EH. The viscosity of the ethanolic resin solutions increased with the molecular weight but was independent on the resin's degree of modification. The drying performance was improved with increasing molecular weight and decreasing modification with 2EH. The hardness of the paint films was proportional to the modification of the resins with TMPDA and the molecular weight. 2EH led to the plasticization of the coatings. The water resistance of the paint films was improved with increasing modification with 2EH and molecular weight of the resin. The analysis of the elastic properties of the hardened films was not possible due to the scatter of the experimental data. The comparison of the amino resin paints to some commercial paint products indicated that BMMU‐based resins having good drying performance and adequate water resistance at the same time can be prepared. Neutral ethanolic and aqueous ethanolic resin solutions were found to have a good storage stability as determined by following the viscosities of the solutions and the hydrolysis resistance of the resins.
The accessibility of sulphonic acid groups in basic dyeable polyester fibers. II. The influence of plasticization on the ion exchange process
Authors: Ingamells W. , Lilou S. H. , Peters R. H. 
Published: April 2003

AbstractThe exchange of the sodium ions of the sodium sulphonate group in anionically modified polyester fibers has been measured. The accessibility of the sulphonate groups in the polymer is greatly improved by plasticization and is independent of the size of the exchanging ion.
Void formation in a filled SBR rubber determined by small‐angle X‐ray scattering
Authors: Kaneko S. , Frederick J. E. , McIntyre D. 
Published: April 2003

AbstractTwo commercial styrene‐butadiene (SBR) latexes were used to prepare a model filled material consisting of glassy SBR filler particles about 1000 Å in diameter embedded in a rubbery SBR matrix crosslinked by γ‐radiation. When transparent specimens of this material were extended, voiding occurred, as evidenced by stress whitening and greatly enhanced X‐ray scattering intensity. More voids were formed at higher rates of extension, but voids disappeared when specimens were relaxed. The effects of filler content and cure time of the matrix on the size and number of voids formed were determined by low‐angle X‐ray scattering for a constant extension rate and a constant extension ratio λ = 1.6. The number of voids measured by X‐ray scattering intensity decreased rapidly with time over the 3‐h period of measurement. The number of voids remaining 1 h after extension increased about 40 times as filler content was increased from 15% to 50%. Increasing the cure time from 24 to 96 h increased the number of voids about four times. In contrast, the radius of gyration of the voids formed (250–350 Å) did not depend strongly on time, nor did it depend strongly on the filler content or the cure time of the matrix. Stress relaxation measurements made under the same conditions as X‐ray scattering measurements showed effects typical of filled materials. However, the relaxation of stress (which followed a power law decay) was much slower than the decay of the number of voids as measured by X‐ray scattering intensity.
Dynamic mechanical properties of an acetylene‐terminated quinoxaline system under air/nitrogen cure
Authors: Lee C. Y.‐C. 
Published: April 2003

AbstractTorsional impregnated cloth analysis (TICA) temperature scan results of an acetylene‐terminated quinoxaline system indicated the presence of two different reactions with different activation energies. Two additional effects are delineated when cure is carried out in the presence of air. Curing at low temperature in the presence of air will lower the final Tg, but at high temperature it will have the opposing effect. The two reactions that can occur under nitrogen are affected differently by air curing. It appears that one is prohibited by the lower temperature curing in air while the other is not.
The flowing‐afterglow technique, and approach to the study of polymer thermal degradation
Authors: Matuszak Michael L. , Taylor Gene W. 
Published: April 2003

AbstractWe describe here a relatively new analytical method1–3 for following the thermal reaction history of polymers by quantitatively detecting the evolution of gases and some volatiles by flowing‐afterglow spectroscopy. The thermal and oxidative stability of common plastics in many industrial and defense applications is of wide interest. We have studied the evolution of moisture and carbon dioxide from Li2CO3/Orlon‐filled diallyl phthalate (DAP) composites and have briefly examined the thermal stability of Estane 5703, a polyester‐based thermoplastic polyurethane. The results of these preliminary studies have shown the utility of FLAG spectroscopy as a means toward our understanding polymer stability and lifetimes in specified environments. FLAG data, combined with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) data, have extended our knowledge of Li2CO3/Orlon/DAP and Estane aging processes. The DAP composites evolve H2O and CO2 at near ambient temperatures, and we have described the kinetics of gas evolution and have attempted to describe the mechanism of thermal degradation. In the 25–120°C temperature range Estane 5703 evolves CO2 as a decomposition product and some adsorbed moisture.
Graft polymerization of methyl methacrylate onto wool using dimethylaniline/copper(II) system
Authors: Khalil M. I. , El‐Rafie M. H. , Bendak A. , Hebeish A. 
Published: April 2003

AbstractDimethylaniline (DMA)/CuII‐induced grafting of methyl methacrylate (MMA) onto wool fibres was studied under different conditions. The grafting reaction was found to be influenced by CuII, DMA, and MMA concentrations as well as polymerization temperature, reaction time, and polymerization medium. While the graft yield increased by increasing the amount of MMA from 100 to 500 mmol/L, maximum grafting occurred at 0.5 mmol/L CuSO4, 10 mmol/L DMA. The graft yield increased by increasing the reaction time from 15 to 150 min and by raising the polymerization temperature from 60 to 80°C. Using dimethylformamide/water and ethyl alcohol/water mixture as a medium for grafting decreased the graft yield, while using isopropyl alcohol/water mixtures increased the graft yield as compared to pure aqueous medium.
The study on radiation grafting of acrylic acid onto fluorine‐containing polymers. III. Kinetic study of preirradiation grafting onto poly(tetrafluoroethylene–hexafluoropropylene)
Authors: Hegazy El‐Sayed A. , Ishigaki Isao , Dessouki Ahmed M. , Rabie Abdelgawad , Okamoto Jiro 
Published: April 2003

AbstractA kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene–hexafluoropropylene) (FEP) film. The effect of grafting conditions was investigated. The dependencies of the grafting rate on preirradiation dose and monomer concentration were found to be 0.58 and 1.25 order, respectively. The overall activation energy for the graft polymerization was 7.4 kcal/mol. The final degree of grafting increased with preirradiation dose and monomer concentration and slightly decreased as the grafting temperature was elevated. The relationship between the grafting rate and film thickness gave a negative first‐order dependency, which is in agreement with that obtained for polytetrafluoroethylene—AAc grafting system. It was reasonably concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution.
Miscibility of poly(caprolactone)/chlorinated polypropylene and poly(caprolactone)/poly(chlorostyrene) blends
Authors: Allard Danielle , Prud'homme Robert E. 
Published: April 2003

AbstractPoly(caprolactone) (PCL) was blended with poly(chlorostyrene) (PSCI) and chlorinated polypropylene (PPCl). A single glass transition temperature Tg was found for these mixtures, indicating their miscibility. PCL crystallizes in these blends when the chlorinated polymer content is not too high. Otherwise, Tg becomes higher than the melting point of PCL and the high viscosity of the medium hinders the crystallization. The miscibility of PCL/PPCI blends cannot be due to hydrogen bonding between the α‐hydrogens of the chlorinated polymer and the carbonyl group of the polyester since PPCI does not have available a large number of α‐hydrogens. It is suggested that a dipoledipole CO…ClC interaction is responsible for the observed miscibility phenomenon and that this interaction is probably also responsible for the miscibility between all other polyesterchlorinated polymer mixtures. Finally, it was observed that poly(α‐methyl‐α‐n‐propyl‐β‐propiolactone), poly(α‐methyl‐α‐ethyl‐β‐propiolactone) and poly(valerolactone) are not miscible with PSCI or PPCl, despite the fact that they are miscible with poly(vinyl chloride).
Reverse osmosis rejection by hydrous inorganic precipitate–cellulose composite membrane
Authors: Kurokawa Yōichi , Ueno Kaoru 
Published: April 2003

AbstractComposit membranes were prepared by impregnating hydrous inorganic precipites (Fe and Cr oxides, nickel chromate or molybdate) into a cellulose acetate membrane which serves as a support. In these membranes, the hydrous iron oxide composite membrane showed high reverse osmosis properties. The permeability of the composite membrane did not decline with time, and the rejection of organic solute was not appreciably affected by impregnation. However, the rejection of electrolyte increased with impregnation. The measurements of membrane potential revealed that salt rejection is primarily attributable to the effect of membrane charge, i.e., to ion exclusion effect. In electrolyte solutions of 1:1 and 2:1, the membrane was anion selective; on the other hand, in electrolyte solution of 1:2, the membrane was cation selective. These results are characteristic of impregnated hydrous metal oxide.
Polyelectrolyte behavior of chemically modified cotton cellulose
Authors: Shet R. T. , Yabani A. M. 
Published: April 2003

AbstractIon exchange and sorption of charged molecules such as dyes, crosslinking agents, etc., by cotton cellulose very much depend on the charge on cellulose, which in turn is known to depend on the external pH of the medium. In order to understand the role of various fixed groups in cellulose in its polyelectrolyte behavior, the standard cellulose was deliberately oxidized with nitrogen dioxide and sodium periodate, and the sorption of formaldehyde and dimethylol dihydroxyethylene urea by these oxycelluloses as well as by alkali‐treated nitrogen dioxide–oxycellulose was investigated. The results obtained are interpreted in terms of polyampholyte behavior of oxycellulose. The nitrogen dioxide–oxycellulose is positively charged and is a polycation in acidic medium due to protonation of aldehyde groups while it is negatively charged and acts as a polyanion in slightly acidic to alkaline medium due to dissociation of carboxyl groups.