bluuebunny/crossref_metadata_2025_split huggingface dataset:
NG‐migration into double‐base inhibitors. I. Sorption
Authors: Potgieter H. F. , Sanderson R. D. 
Published: April 2003

AbstractDouble‐base propellants are inhibited with polymeric material to restrict the burning surface. The energetic plasticizer may migrate out of the propellant into the inhibitor. This may then cause the inhibitor to deteriorate. Thus, the measurement of the amount of energetic plasticizer that migrates into the inhibitors is important.Sorption measurements are done using a “sandwich” test. The data obtained are used in an empirical formula to calculate the maximum amount of energetic plasticizer that will be absorbed by a particular polymer. The validity of the formula is confirmed. © 1993 John Wiley & Sons, Inc.
Wet spinning of chitosan and the acetylation of chitosan fibers
Authors: East George C. , Qin Yimin 
Published: April 2003

AbstractChitosan fibers were made by wet spinning of its solution in 2% aqueous acetic acid. The fiber properties were affected by processing conditions, such as spin stretch ratio, coagulation bath composition, and drying conditions. The chitosan fibers were acetylated with acetic anhydride in methanol, producing regenerated chitin fibers. The acetylation process was affected by the reaction temperature, the treatment time, and the molar ratio of anhydride to amine groups. The properties of the acetylated chitosan fibers were studied in terms of thermal stability, solubility, and mechanical properties. It was found that, after acetylation, the fibers had an improved thermal stability and tensile strength. © 1993 John Wiley & Sons, Inc.
Equation of state predictions of sorption isotherms in polymeric materials
Authors: Hariharan R. , Freeman B. D. , Carbonell R. G. , Sarti G. C. 
Published: April 2003

AbstractThe ability of the Sanchez‐Lacombe equation of state to predict the solubility of small penetrants in rubbery polymer matrices, over a wide range of ambient pressures, is examined critically. The solute chemical potential and, in turn, the resulting predicted isotherms are found to depend strongly on solute equation of state parameter values and on the mixing parameter for polymer‐penetrant interactions. The isotherms are less sensitive to polymer equation of state parameters. In the sorption of organic vapors into polymers, the model does not describe well the sorption isotherms at high values of penetrant activity. The model appears to describe sorption isotherms most accurately when both polymer and penetrant equation of state parameters are determined from pure component properties, in the same temperature and pressure range as the sorption data, and when a mixing parameter is used to adjust the fit of the model to the data. © 1993 John Wiley & Sons, Inc.
Mechanisms of antioxidant action: Nature of transformation products of dithiophosphates. Part III. The antioxidant action of dithio and thio/thionophosphoric acids
Authors: Al‐Malaika S. , Coker M. , Scott G. , Smith P. 
Published: April 2003

AbstractThe nature of transformation products of dithio‐ and thionophosphoric acids in the presence and absence of hydroperoxides and their role as transformation products formed during oxidation of thiophosphoryl disulfide at high temperatures is investigated. The major transformation product of dithiophosphoric acid was found to be the corresponding disulfide while thiophosphoric acid was the major oxidation product of the reaction of thionophosphoric acid with hydroperoxide. In the case of thiophosphoryl disulfide, it is shown that thionophosphoric acid was found to be one of the major transformation products in the presence of hydroperoxides, whereas no acids were formed in the absence of added hydroperoxides. © 1993 John Wiley & Sons, Inc.
Solubility of binary liquid mixtures in polymeric materials
Authors: Vahdat Nader 
Published: April 2003

AbstractExperimental data on the permeation of binary mixtures through polymeric materials show that liquid mixtures can exhibit large, positive synergistic rates. As the permeation rate depends on both solubility and the diffusion coefficient, the existence of a maximum in the steady‐state permeation rate vs. the composition curve could be due to an increase in solubility and/or diffusion coefficient. In this study, a theoretical model based on the Flory‐Huggins equation was developed to predict the solubility of binary liquid mixtures in polymers. The equation has four adjustable parameters that can be determined from solubilities of pure liquids in the polymer and the vapor‐liquid equilibrium data for the binary liquid mixture. The model was tested for two binary liquid mixture/polymer systems. The predicted values of solubilities are close to the experimental data. © 1993 John Wiley & Sons, Inc.
Determination of glass transition temperature from viscosity and conductivity measurements for an epoxy–amine system during curing
Authors: Koike Tsuneo 
Published: April 2003

AbstractThe melt viscosity and the direct current (dc) conductivity have been investigated for three bisphenol‐A novolac‐type epoxide oligomers (PGEBANs) that have some branching in each molecule in comparison with the diglycidyl either of bisphenol‐A (DGEBA) oligomer without branching. The novolac‐type PGEBAN oligomer has an experimental relationship between the melt viscosity (η) and the dc conductivity (σ), σ.ηk = const, which is the same form observed for the DGEBA oligomer. The exponent k has a linear relationship with the glass transition temperature (Tg) for the two types of oligomers with and without branching. The Tg dependence of k for the epoxide oligomers was used to analyze the Tg of a DGEBA—amine system that had some degree of branching in the molecule based on the bisphenol‐A structure. The Tg of the DGEBA—amine system, which was calculated from the k that had been nondestructively determined from the viscosity and the conductivity measurements, was consistent with the Tg experimentally measured by differential scanning calorimetry (DSC). © 1993 John Wiley & Sons, Inc.
Stress–optic relation and photo‐viscoplasticity for plastically deforming polymer solids
Authors: Nishitani Tadashi , Tsuji Masatoshi , Suetsugu Masahiro , Ogura Hiroyuki 
Published: April 2003

AbstractPhoto‐viscoplasticity for finding the stress distribution in a plastically deforming polymer solid is discussed by using the deduced stress‐optic relation. As an example, a practical application is shown for tension of the strip having semicircular notches in the plane stress state. © 1993 John Wiley & Sons, Inc.
Oxetane formation by addition of N‐substituted imidazoles to benzophenone and poly(4‐vinylbenzophenone)s
Authors: Ito Yoshikatsu , Kusunaga Yoshitaka , Tabata Kenichi , Arai Hitoshi , Meng Ji‐Ben , Matsuura Teruo 
Published: April 2003

AbstractPhotochemical oxetane formation by addition of 1‐methyl‐2,4,5‐triphenylimidazole (1a), 1,2‐dimethyl‐4,5‐diphenylimidazole (1b), and 1‐acetylimidazole (1c) to benzophenone (BP), poly(4‐vinylbenzophenone) (PVBP), and poly(styrene‐co‐4‐vinylbenzophenone) (PSVBP) was studied in the solution and solid phases. In solution, BP underwent the photoaddition smoothly to all three imidazoles 1a–1c. On the other hand, the photoaddition of PVBP and PSVBP depended on the imidazole employed, that is, 1b and 1c produced the corresponding oxetane, but 1a did not. The lack of oxetane formation from the polymeric BP and 1a is probably due to a rapid triplet‐sensitized decomposition of a once‐formed oxetane ring as a result of the intramolecular triplet energy transfer from a pendant benzophenone group. © 1993 John Wiley & Sons, Inc.
Model esterification of isophthalic and terphthalic acid with benzyl alcohol
Authors: Braam Ad W. M. , Scholtens Boudewijn J. R. 
Published: April 2003

AbstractThe esterification kinetics of isophthalic and terephthalic acid, with benzyl alcohol, were studied in the melt phase, which is a heterogeneous system because of the low solubilities of the phthalic acids. The relative concentrations of components and their conversions, α, were determined with HPLC. The effect of insolubility of the phthalic acids on the reaction kinetics can be described in two ways. For terephthalic acid, at 0 ≤ α ≤ 1, and for isophthalic acid, at α < 0.6, the esterification kinetics can be described with equations for a homogeneous system with only a substitution effect. An improved and more complete description for isophthalic acid is obtained with equations for a heterogeneous system, with a surface reaction rate constant and a ratio of reactive (at the surface) over nonreactive monomers (in the core, i.e., the surface to volume ratio). This model fits data for α < 0.7. The model parameters depend on the reaction temperature and the solubility of the phthalic acid. © 1993 John Wiley & Sons, Inc.
Carbon fiber heat treatment temperature and electrophysical properties of composite materials filled with these fibers
Authors: Letyagin S. V. , Shevchenko V. G. , Ponomarenko A. T. , Kestelman V. N. 
Published: April 2003

AbstractConductivities of composites filled with different carbon fibers having different heat treatment temperatures (HTT) have been studied. It is shown that conductivity realization coefficient decreases with the increase of HTT. © 1993 John Wiley & Sons, Inc.
An adhesion study of poly(phenylquinoxaline) on silicon wafers
Authors: Mcgarvey C. , Beccat P. , Zanier‐Szydlowski N. 
Published: April 2003

AbstractThis study is an investigation of the adhesion between poly(phenylquinoxaline) (PPQ) and γ‐aminopropyltriethoxysilane (γ‐APS)‐treated silicon wafers. In order to determine the locus of failure of the PPQ film‐coated wafers, when the coating was mechanically removed from the surface, the surface‐sensitive techniques of X‐ray photoelectron spectroscopy and contact angle measurements were employed. This permitted an analysis of the surface that was exposed when the film was removed from the substrate. In addition, FTIR spectroscopy was used to study the effect of the thermal treatment of the film‐coated wafers on the silane layer. Treatment of the coated wafers up to temperatures in excess of 250°C caused a deterioration of the γ‐APS layer, leading to a loss in adhesion of the coating, which was likely a result of the decrease in the density of the PPQ chains, which become anchored in the silane layer as the silanol groups condense during curing. When treatment temperatures are allowed to reach 400°C, the silane layer becomes severely degraded. It was found that the locus of failure remained the same, regardless of whether or not the coated wafer was subjected to aging in boiling water. © 1993 John Wiley & Sons, Inc.
Characterization of water‐soluble oligomer in acrylic acid‐styrene emulsion copolymerization
Authors: Wang Shou‐Ting , Poehlein Gary W. 
Published: April 2003

AbstractLow molecular weight species, formed during the emulsion copolymerization of styrene and acrylic acid, were isolated and characterized. Samples of the reaction mixture were taken at different times during seeded and unseeded batch reactions. Reactions were stopped via injection of the samples into hydroquinone solutions and cooling with dry ice. Low molecular weight copolymers were separated and FTIR spectroscopy, mass spectroscopy, and 13C–NMR spectroscopy techniques were used to measure the oligomer composition, molecular weight, and copolymer sequence distribution, respectively.The molecular size measurements should relate to the size of oligomeric radicals that grow in the water phase and enter polymer particles and the measurements should also relate to any water‐soluble polymer that is formed by termination in the aqueous phase. The molecules, found for copolymers formed from 90/10 weight ratios of styrene and acrylic acid, were comprised of 6–9 monomer units with 2–3 being styrene. Those formed from 60/40 styrene/AA ratios contained 13–16 monomer units with 1–2 styrene. Differences were observed between seeded and unseeded systems, especially in the amount and nature of the water‐soluble material formed early in the reaction. © 1993 John Wiley & Sons, Inc.
Benzophenone‐containing methylthiomethyl pendant polyimides as negative acting photoresists
Authors: Chiang Wen‐Yen , Mei Wang‐Ping 
Published: April 2003

AbstractFour kinds of benzophenone‐containing polyimides, each of which carries different amount or distribution of methylthiomethyl (MTM) pendant groups, are applied as negative photoresists. Lithographic evaluation of these polyimides shows that PI‐42, the polyimide possessing the most, i.e., three MTM groups in a repeating unit on average, exhibits the highest sensitivity (D = 129 mJ/cm2), the highest contrast value (γ = 4.3), and the highest resolution capability (1.2‐μm lines and spaces can be resolved in a 1.0 μm thick film). In the air, the photopatterned lines obtained from all these polyimides are thermally stable up to 280°C. Upon treating at 400°C for 30 min, a 8% reduction in the linewidth is observed for the 3.8‐μm line of PI‐42. The optimum developing conditions of each of these title polymers are determined. Contrast curve analysis indicates that this resist system exhibits higher sensitivity at near UV region than at deep UV region. © 1993 John Wiley & Sons, Inc.
Polymeric photoinitiators bearing side‐chain benzoyldiphenylphosphinoxide moieties for UV curable coatings
Authors: Angiolini Luigi , Caretti Daniele , Carlini Carlo 
Published: April 2003

AbstractPolymeric photoinitiators bearing side‐chain benzoyldiphenylphosphinoxide moieties have been prepared by reacting poly(4‐vinylbenzoic acid) or 4‐vinylbenzoic acid/methyl methacrylate copolymers with thionyl chloride followed by methoxydiphenylphosphine. The activity of the above polymeric systems has been checked in the UV curing of the acrylic clear‐coating formulation HDDA/BA and compared with that of the low molecular weight model 4‐isoprophylbenzoyldiphenylphosphinoxide. The stability to light and to hydrolytic conditions of the polymeric photoinitiators with respect ot the model has also been tested. The results obtained are discussed in terms of composition and structural features of these systems. © 1994 John Wiley & Sons, Inc.
Blend rules for homogenous and heterogenous systems
Authors: Furukawa Junji 
Published: April 2003

AbstractBlend rules for (a) homogeneous and (b) heterogeneous systems are proposed in a form of P = (ϕm1P1 + ϕm2P2)/(ϕm1 + ϕm2), where P is the property, and ϕ, the volume fraction of component 1 or 2. For (a) m>1 and for P2>P1, an S‐shaped relation occurs between P or ϕ1. On the contrary, for (b) m<1, an anti‐S‐shaped relation occurs. When the hard component forms particles in continuous soft media, P is larger than the arithmetic mean P̄. When the interface slips, a mean of harmonic function holds so that 1/P = ϕ1/P1 + ϕ2/P2 and P < P̄. For special cases, i.e., the filler in the rubber and the rubber particles in the resin, the strength at break attains a maximum at 20 and 13% of particles, respectively. For rubber blended with a small amount of polypropylene by dynamic vulcanization, the latter forms a continuous phase, reinforcing rubber domains by the plastic force when the size of rubber particles becomes very small. © 1994 John Wiley & Sons, Inc.
Synthesis of zinc‐containing epoxy resin
Authors: Anand Manjit , Srivastava A. K. 
Published: April 2003

AbstractNovel epoxy resins containing zinc acrylate have been synthesized by reacting zinc acrylate with bisphenol‐A and an excess of epichlorohydrin. Parameters such as epoxy equivalent weight, hydroxyl content, and hydrolyzable chlorine content have been estimated. These resins, characterized by IR, 1H‐NMR, and 13C‐NMR, have been evaluated by thermal analysis. Curing was carried out with polyamide at 130°C for 24 h. Cured resins have improved thermal and chemical resistance. The reaction follows first‐order kinetics with activation energy 86 and 34 kJ mol−1 in the presence and absence of zinc acrylate. The role of zinc, which increases epoxidation due to formation of complex with bisphenol‐A, has been discussed. © 1994 John Wiley & Sons, Inc.
A tensile rheometer for solid polymers containing volatile diluents
Authors: Monahan M. D. , Durning C. J. 
Published: April 2003

AbstractA tensile rheometer capable of confining diluent is described. This rheometer makes it possible to characterize solid samples with imbibed diluent. Tensile stress‐relaxation data were obtained as a function of temperature for dry glassy semicrystalline poly(ethylene terephthalate) (PET) and as a function of composition for semicrystalline PET imbibed with dimethlformaide (DMF). Data on PET/DMF captures the glass‐rubber transition as DMF content is increased. © 1994 John Wiley & Sons, Inc.
Poly(ethylene terephthalate)/polyarylate blends: Mixing and interchange reactions in injection molding
Authors: Martínez J. M. , Nazábal J. , Eguiazábal J. I. 
Published: April 2003

AbstractBlends composed of poly(ethylene terephthalate) and a polyarylate have been melt‐mixed and molded in a reciprocating screw injection‐molding machine for different plasticization times. Interchange reactions between the blend components occur during processing and at a greater level as the plasticization time increases. These reactions led to a progressive homogenization of the blends as well as to a hindered crystallization of PET. The effect of the plasticization time on the mechanical properties of the blends seems to be a consequence of interchange reactions as well as of the degradation of the blends at the highest plasticization times. © 1994 John Wiley & Sons, Inc.
Importance of solubility phenomena during the separation of the ethylene–polyethylene mixture in the industrial low density polyethylene process
Authors: Bogdanović Vojislav Ž. , Tasić Aleksander Ž. , Djordjević Bojan D. 
Published: April 2003

AbstractThe solubility values of ethylene in polyethylene and vice versa have been evaluated for the process conditions. These results could be used in solving real problems of PE‐LD process. © 1994 John Wiley & Sons, Inc.
A rheological and morphological explanation of the inherent blocking force in LLDPE blown films
Authors: Hazlitt Lonnie G. , Karande Seema V. , Castille Merrick J. 
Published: April 2003

AbstractThe inherent film blocking force in linear low‐density polyethylene (LLDPE) blown films was studied using several LLDPEs with varying density, molecular weight, and molecular weight distribution (MWD). Melt elasticity, fabrication conditions, and film surface morphology were found to have a significant effect on the inherent film‐blocking force in LLDPE blown films. A comprehensive mechanism for the film‐blocking force based on molecular weight, rheology, and morphology studies is proposed. LLDPEs with higher density exhibited a lower blocking force. At a constant density, the LLDPEs with higher melt elasticities (slower relaxation rates) exhibited rougher film‐surface morphology and produced blown films with lower blocking force. These LLDPEs with an inherent low blocking force are used in grocery sacks, trash bags, and merchandise bag markets where bag openability is a critical performance property. © 1994 John Wiley & Sons, Inc.
XPS study of dimethylolurea polymers and hollow fibers modified by these polymers. I. XPS study of dimethylolurea polymers
Authors: Rouzies P. , Lebugle A. 
Published: April 2003

AbstractPolycondensation of dimethylolurea leads to the formation of a gel or a film according to the experimental conditions. Both forms of the polymer would be characterized by a specific chemical structure, i.e., dimethylene ether or diaminomethylene, respectively. We studied both forms of dimethylolurea polymer by XPS and have shown that it is possible to distinguish them using this technique. The study of the carbon peak shape attributed mainly a dimethylene ether structure to the gel and a diaminomethylene structure to the film. © 1994 John Wiley & Sons, Inc.
Physical characteristics of silk fibers modified with dibasic acid anhydrides
Authors: Tsukada Masuhiro , Gotoh Yoko , Shiozaki Hideki , Freddi Giuliano , Crighton John S. 
Published: April 2003

AbstractThe objective of this study was to investigate the physical properties of silk fibers modified with dibasic acid anhydrides. These are potentially attractive modifying agents to reduce the rate of photoyellowing of silk during and following UV irradiation. Several analytical techniques were employed, which included the measurement of the basic mechanical properties (tensile strength and elongation at break), equilibrium regain, amino acid analysis, dynamic viscoelastic measurements, X‐ray diffractometry, and scanning electron microscopy (SEM). The succinylated silk fibers, which have been conditioned under different relative humidity atmospheres, always exhibited slightly higher equilibrium regain values than those of equivalently conditioned glutarylated silks. The amount of the basic amino acid residues slightly decreased following modification with both succinic and glutaric anhydrides. The birefringence values and the isotropic refractive indices decreased only slightly, which suggests that the fine structure of the treated silk fibers was not significantly altered. The X‐ray diffraction curves demonstrated that no changes in the crystalline structure were induced by reaction with dibasic acid anhydrides. The tensile properties of the modified silks remained more or less unchanged. Only the initial tensile resistance of glutarylated silks in the dry state significantly decreased. The dynamic viscoelastic behavior of modified silk fibers was characterized by a reduced thermal stability. In fact, the onset temperature of the prominent E peak corresponding to the molecular movement shifted to lower values. The surfaces of modified silk fibers were as smooth as that of the untreated control sample. © 1994 John Wiley & Sons, Inc.
Electric‐field‐sensitive polymers: Reversible bending of rod‐shaped polymer gels in salt solutions
Authors: Choi Oe Soon , Yuk Soon Hong , Lee Hai Bang , Jhon Mu Shik 
Published: April 2003

AbstractNeutral gel (acrylamide [AAm] gel) and anionic gel (copolymer gel of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid [AMPSA] and butyl methacrylate [BMA]) were prepared to observe the bending phenomena in various salt solutions. The bending pattern of AAm gel was closely related to salts used in the aqueous media. The competition NMR technique was used to understand the interaction of salts with the polymer matrix. In the case of copolymer gel, the bending pattern did not show the salt dependence and the bending angle decreased after reaching a maximum. © 1994 John Wiley & Sons, Inc.
Photo‐ and thermal‐oxidation of the nonwoven polypropylene fabric studied by FT‐IR photoacoustic spectroscopy
Authors: Yang Charles Q. , Martin Linette K. 
Published: April 2003

AbstractThe photo‐ and thermal‐oxidation of a nonwoven polypropylene fabric was investigated using Fourier transform infrared photoacoustic spectroscopy (FT‐IR/PAS). The infrared spectroscopic data indicate that alcohol, peroxide, aldehyde, ketone, carboxylic acid, and anhydride were formed as the products of the thermal oxidation and photooxidation of the polypropylene fabric. Ester was also formed during the thermal oxidation process. The thermal oxidation was accelerated after an initiation period. It was found that thermal oxidation occurred homogeneously between the surfaces of the fabric and its bulk. For the polypropylene fabric irradiated by ultraviolet (UV) radiation, however, the highest degree of oxidation occurred in the surface of the fabric facing the UV radiation source. It was also found that the UV radiation at 254 nm caused photooxidation of polyropylene. No photooxidation was observed in the fabric exposed to the UV radiation at 350 nm under the same conditions. © 1994 John Wiley & Sons, Inc.