bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of hydrofuramide on network structure and kinetics of thiuram vulcanization
Authors: Banerjee B. , Chakravarty S. N. , Biswas A. B. 
Published: April 2003

AbstractThe influence of hydrofuramide (a reaction product of furfural and ammonia) on the network structure and overall kinetics of thiuram vulcanization of natural rubber is reported. The nature of the network structure of the thiuram vulcanizates in the presence and absence of hydrofuramide was determined using triphenyl phosphine (Ph3P) as a chemical probe. The presence of hydrofuramide produces structural complexity of the vulcanizate. The overall kinetics of thiuram vulcanization follows a first‐order‐rate law in the presence as well as in the absence of hydrofuramide. The rate constant increases while the energy of activation decreases in the presence of hydrofuramide.
Formation of polyelectrolyte complex and its adsorption properties
Authors: Kurokawa Yōichi , Shirakawa Namio , Terada Manabu , Yui Norio 
Published: April 2003

AbstractPolyeletrolyte complex formations between two oppositely charged polyions[ionene, poly(vinylbenzyl trimethylammonium chloride), poly(diallyl dimethylammonium chloride), polyaminesulfone, potassium poly(vinyl sulfate), sodium poly(stylene sulfonate), poly(acrylic acid)] have been investigated by conductance and trubidity measurements. It was found that the complex formation of these polyelectrolytes formed in stoichiometry. Adsorption isotherms of water, methanol, acetone, and benzene were determined for the resulting complexes at 25°C with a gravimetric adsorption apparatus. The differences in adsorption can be exclusively ascribed to differences in ion site and hydrophobic circumstances around the ion site, since each complex has a low specific surface area (<1 m2/g). Amount of adsorption increased in the order of water > methanol > acetone > benzene. This order corresponds to that of the polarity of adsorbate.
Effect of nonionic surfactant and heat on selected properties of nylon 6,6
Authors: Needles Howard L. , Lu Wen‐Chu , Alger Kenneth , Varma D. S. 
Published: April 2003

AbstractHeat treatment of nylon 6,6 in the temperature range of 100–175°C in the presence and absence of a nonionic surfactant (Triton X‐100) had little effect on the physical properties of the nylon, although the density of the nylon increased with increasing heat treatment temperature. The moisture regain value for the treated nylons did not change substantilly, whereas the overall wettability of the heat‐treated nylon in the presence of nonionic surfactant showed a marked improvement. Both heat treatment of the nylon alone or in the presence of surfactant had a substantial effect on the uptake of three 1,4‐substituted anthraquinone dyes on the nylon and on the resultant color of the dyed nylon.
Heat transfer to molten polymer flow in tubes
Authors: Agur E. E. , Vlachopoulos J. 
Published: April 2003

AbstractThis article presents the results of a numerical study (finite differences) of the heat transfer problem in flowing polymer melts. The tube wall is assumed to be at a constant temperature. The rheological behavior of the melt is described by a power law temperature‐dependent model. A convective and a viscous dissipation term are included in the energy equation. Temperature profiles, bulk temperatures, and Nusselt numbers are presented for a variety of flow entry temperatures.
Dry sintering of latex particles in pigmented coatings. I. Influence on coating structure and properties
Authors: Lepoutre P. , Alince B. 
Published: April 2003

AbstractWhen a clay–latex coating, dried below the minimum film‐forming temperature (MFT) of the latex, was subsequently heated above the MFT, its opacity and brightness were considerably enhanced. The improvement in optical properties was optimum in the latex content range of 20–40 parts per 100 parts of clay. The sintering of the latex particles, brought about by the thermal treatment, increased the average size of the microvoids to a diameter that is optimum for the scattering of light, without significantly affecting the total void content. Data on light‐scattering coefficient, porosity, gloss, brightness, and oil permeability are discussed and compared to those of conventional coatings, i.e., of coatings dried above the MFT of the latex. Similar improvements in optical properties were obtained when coalescence of the latex particles was induced by exposure to a solvent.
Improving antistatic properties of poly(methylvinylpyridine)–poly(ethylene terephthalate) graft copolymers via alkylation
Authors: El‐Shahed M. F. , Shalaby S. E. , Hebeish A. 
Published: April 2003

AbstractThe alkylation reaction of poly(methylvinylpyridine)–poly(ethylene terephthalate) graft copolymers with different alkylating agents using monochloroacetic acid has proved to be the best as far as degree of alkylation and enhancement in electrical conductivity caused thereby are concerned. Kinetic investigation revealed that alkylation follows a second‐order reaction, and the apparent activation energy is 15.23 cal/mole.
Resolution in column chromatography of polymer latexes. I. The light scattering behavior of polystyrene and its effect on signal resolution in HDC
Authors: Nagy D. J. , Silebi C. A. , McHugh A. J. 
Published: April 2003

AbstractA method for improving signal resolution in latex particle‐size analysis by HDC is presented and discussed. Data for the extinction cross section and specific extinction coefficient for polystyrene latex standards indicate that improvements in signal resolution can be obtained for the small particle end of broad size distributions by using turbidity detection at wavelengths less than 254 nm. Data are also discussed for the imaginary refractive index of the polystyrene standards obtained from comparisons of the extinction cross section results with Mie theory calculations. HDC runs made with bimodal and continuous distributions at 254 and 220 nm wavelength detection are also discussed to illustrate the improvements in size distribution resolution which can result.
Resolution in column chromatography of polymer latexes. II. A comparison of porous and nonporous packing systems
Authors: Nagy D. J. , Silebi C. A. , McHugh A. J. 
Published: April 2003

AbstractData are presented to compare the size separation capabilities of several porous packing systems for latex particle chromatography. Material balance problems as well as nonequilibrium behavior encountered with small‐pore systems (pores less than 1 μm) lead to the conclusion that larger pore systems (diameter 2 μm or greater) are superior from an operational viewpoint. The separation mechanism for a large‐pore Fractosil system is shown to be predominantly hydrodynamic in nature with flow separation occurring in both the pores and packing interstices. The name Hydrodynamic Permeation Chromatography, or HDPC, is used to describe the process. The effects of calibration slope and band broadening on peak resolution are compared for an HDC system and the Fractosil system indicating the superior resolving power of the HDC system. Qualitative and semiquantitative considerations are made with regard to improved porous packing characteristics for an ideal HDPC system which would improve separation efficiency and resolution.
Synthesis of cationic flocculant by radiation‐induced copolymerization of methyl chloride salt of N,N‐dimethylaminoethyl methacrylate with acrylamide in aqueous solution. II. Copolymerization at higher monomer concentration
Authors: Ishigaki Isao , Fukuzaki Hironobu , Okada Toshimi , Okada Toshio , Okamoto Jiro , Machi Sueo 
Published: April 2003

AbstractThe radiation‐induced copolymerization of methyl chloride salt of N,N‐dimethylaminoethyl methacrylate with acrylamide was studied to prepare a polymer flocculant that can be handled as a solid. The product obtained in the presence of 5–20% water was a solid and could be ground to a powder without drying. In order to obtain a water‐soluble polymer at a higher concentration, the effect of various additives on the copolymerization was investigated and found that alcohols bearing a hydrogen atom attached to the tertiary carbon atom effectively inhibit intermolecular crosslinking to give water‐soluble polymer. It is suggested that the formation of water‐insoluble polymer is predominantly attributable to the crosslinking of polymer chains rather than to the imidation of amide groups. Copolymerization in the presence of isopropyl alcohol as inhibitor of the crosslinking was also studied and compared with that reported previously, which was carried out at a lower monomer concentration without additives.
Effect of 1.33 MeV γ radiation and 0.5 MeV electrons on the mechanical properties of graphite fiber composites
Authors: Fornes R. E. , Memory J. D. , Naranong N. 
Published: April 2003

AbstractEpoxy/graphite fiber, polyimide/graphite fiber, and polysulfone/graphite fiber composites were exposed to 1.33 MeV γ irradiation and 0.5 MeV electron bombardment for varying periods of time. The effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test. Effects were small; indeed, both electron radiation up to 5000 Mrad and γ radiation up to 350 Mrad resulted in slight increases in both stress and modulus.
Determination of the hindered amine additive CGL‐144 in polypropylene by high‐performance liquid chromatography
Authors: Schabron J. F. , Bradfield D. Z. 
Published: April 2003

AbstractA method was developed to determine CGL‐144 (Tinuvin 144) in polypropylene. Polypropylene pellets were dissolved in hot decalin. The solution was cooled to precipitate the polymer. A portion of the filtered extract solution was injected onto a normal‐phase high‐performance liquid chromatography (HPLC) system consisting of a μ‐Porasil stationary phase and a chloroform:ethanol:ammonia (95:5:0.05) mobile phase. The amount of CGL‐144 was determined by peak height measurement from an ultraviolet absorption detector set at 280 nm. Injections could be made every 10 min. The limit of detection for the method as described is 0.06% CGL‐144 in polypropylene. There are no known interferences with this method.
Synthesis and characterization of mica—vinyl graft copolymers
Authors: Rao K. Panduranga , Kanniappan E. P. , Jayaraman K. S. , Joseph K. Thomas , Nayudamma Y. 
Published: April 2003

AbstractGraft copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) onto mica was carried out by the ceric ion method. Experiments were carried out both in the presence and absence of oxygen; oxygen has some detrimental effect in the grafting of AN onto mica. Mica—vinyl graft copolymers were characterized using infrared spectra after purifying the crude graft copolymers for the removal of the occluded homopolymers. The percent grafting, grafting efficiency and the ratio of Rg/Rh were determined. Mica—graft copolymers were saponified by treating with aqueous alkali to convert the nitrile groups to carboxyl groups with a view to utilize these groups for coupling to collagen substrates. Since in a chrome‐tanned leather there are available coordination sites due to fixed chromium, the mica—graft copolymer could get bound, thereby resulting in a well filled‐up leather.
Effect of heat treatment on dielectric relaxation of polyacrylonitrile: Reversible thermally induced structural change
Authors: Gupta A. K. , Singhal R. P. , Agarwal V. K. 
Published: April 2003

AbstractThe effect of heat treatment on the dielectric relaxation of polyacrylonitrile (PAN) was studied. Dielectric measurements, in the frequency range 0.1–100 kHz and temperature range 30–170°C, on PAN heat treated at two temperatures (120 and 160°C) and the untreated PAN are reported. The loss peak height, the dielectric relaxation strength, loss peak width, and the loss peak temperature were found to vary systematically with the temperature of the heat treatment. The changes in dielectric relaxation produced by heat treatment at the higher temperature (i.e., 160°C) were considerably less than those produced by heat treatment at 120°C. The results are discussed and attributed to the variation of the degree of bound nitrile groups (through their dipole–dipole interaction) with heat treatment temperature. Heat treatment of the higher temperature (160°C) results in lower degree of bound nitrile groups in the structure than heat treatment at the lower temperature (120°C).
Grafting onto wool. XIV. Graft copolymerization of vinyl monomers by use of Mn(AcAc)3 as an initiator
Authors: Misra B. N. , Sood D. S. , Sharma R. K. 
Published: April 2003

AbstractEthyl acrylate (EA), butyl acrylate (BA), and vinyl acetate (VAc) have been graft copolymerized onto Himachali wool fiber in an aqueous medium by using Mn(AcAc)3 as an initiator. Graft copolymerization was studied at 45°, 55°, 65° and 75°C for various reaction periods. Percentage of grafting and percent efficiency were determined as functions of concentration of monomer, concentation of initiator, concentration of nitric acid, time, and temperature. Several grafting experiments were carried out in the presence of various additives which included: (i) pyridine and (ii) Et3 N. EA, BA, and VAc were found to differ in reactivity towards grafting and followed the order: EA > BA > VAc.
Active transport membrane for anions. III. Effect of crown ether and tautomeric functional groups
Authors: Ogata Naoya , Sanui Kohei , Fujimura Hideo 
Published: April 2003

AbstractMembranes derived from copolymers having N‐hydroxyalkyl groups were prepared, and the active transport for anions through the membranes was investigated in the presence of a crown ether which suppresses the diffusion of counter ions. The maximum of the concentrated anions in one side cell was maintained for a long time by the addition of a crown ether in the cell, and a concentration of anions up to 50% was attained. Various N‐hydroxyalkyl groups of different lengths were incorporated in copolymers with styrene, and the transport for anions was investigated in order to establish the carrier mechanism of the tautomeric functional groups. Longer‐length alkyl moieties bearing N‐hydroxyalkyl groups led to a decrease in the active transport for anions, which supports a carrier mechanism for the membranes.
Continuous measurement of dynamic tensile mechanical properties in polymer solids over a wide range of frequencies. I. An instrument with driving force of 15 kgwt and frequency range 10−3–102Hz
Authors: Yokouchi Mitsuru , Kobayashi Yasuji 
Published: April 2003

AbstractTwo compact apparatuses were designed and fabricated for the study of dynamic mechanical viscoelastic behavior in polymer solids over a wide range of frequencies: (1) 10−3–102 Hz with a tensile driving force of 15 kgwt, and (2) 10–104 Hz with a maximum tensile driving force of 15 kgwt. The present paper reports the details of the instrument of (1). The instrument contains a nonresonant and forced vibration system, where the rectilinear vibration is taken from the rotating shaft of the driving motor through the double eccentric crank and conrod‐slider machineries. Measurements can be conducted at any desirable frequency (10−3‐102 Hz) and displacement (0–2 mm). Subjected to longitudinal vibration, the stress and strain in the specimen are detected by a compression‐type load cell and noncontacting displacement meter, respectively. The specimen clamp was especially devised for the compression‐type load cell, which enables direct conversion from the tensile force on the specimen to the compressive force against the load cell without any medium. Another feature of the instrument is a vertical combination of vibrational driving system, specimen clamp, and load cell. These are important for the effective transmission of the driving force to the specimen and avoidance of unnecessay mechanical vibration noises. From the Lissajous' figure formed with two signals of the stress and strain, the values of dynamic tensile modulus and loss factor for polymeric materials are easily obtained.
Electron spin resonance study of γ‐irradiated nylon 6
Authors: Takigami Shoji , Matsumoto Iwao , Nakamura Yoshio 
Published: April 2003

AbstractThe free radicals trapped in oriented nylon 6 filaments after γ‐irradiation under vacuum at room temperature were studied by ESR spectroscopy. The ESR spectrum measured after irradiation gradually changed to a broad singlet spectrum with decrease in the intensity. The ESR spectrum consisted of radicals with different orientation effects with respect to the outer magnetic field, and saturation effects in reference to microwave power. The simulation of the ESR spectrum from a Gaussian function gave a better fit to the observed spectrum than the calculation from a Lorentzian function. From the resolution of the spectrum from a Gaussian function, the observed spectrum is generated from three kinds of radicals:
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The relative radical concentration for the first, second, and third radical is about 75%, 6%, and 19% of the total radical concentration, respectively. With regard to the stability of the radicals, the third radical shows a comparatively long lifetime. The first and second radicals show almost identical lifetime, and their concentrations reduce to about 40% of the initial value during the 2 days at room temperature.
Calculation of dielectric loss of gamma relaxation process in polyethylene at low temperature
Authors: Sato Yukihiko 
Published: April 2003

AbstractA method has been investigated to obtain the absorption intensity of the dielectric γ relaxation process in polyethylene by calculation. A correlation factor for evaluation of the effective dipole moment of polar groups in solid polyethylene is introduced on the assumption that with expanding distribution of relaxation time and/or increasing temperature, the extent of the canceled dipole moment due to the orientation motions of the polar groups under an alternating electric field will increase. Comparison of the calculated dielectric loss tangent with the observed one supports the assumption.
Some structure‐property relationships in polymer flammability: Studies of phenolic‐derived polymers
Authors: Zaks Y. , Lo Jeelen , Raucher D. , Pearce E. M. 
Published: April 2003

AbstractThe investigation of the thermal degradation of the char‐formaing phenol–formaldehyde resins is conducted to provide information for the systematic design of high temperature flame‐resistant phenolics. Three different processes of curing are used: (1) Formaldehyde or s‐trioxane is reacted with m‐substituted phenol–formaldehyde oligomers under acidic conditions to give the methylene bridged‐novolac resins. (2) Phenol and m‐substituted phenols are reacted with CH2O under basic conditions and then heated to give the methylene bridged resol resins. (3) p‐Terephthaloyl chloride and m‐and p‐substituted novolac oligomers are reacted to give cured resins with ester linkages. The evaluation of the effect of various substituents indicates that the oxygen index (OI) increases from about 33 for unsubstituted phenolics to about 75 for meta‐halogen substituted phenolics. The evaluation of the effect of various crosslinking agents shows that the OI for CH2O‐cured phenolics is 75 as compared to 50 for the trioxane cured phenolics and to 40 for the terephthaloyl chloride cured phenolics. A set of phenolic copolymers with different weight percentage content of halogen substituted phenols are synthesized as novolacs and resols. The results surprisingly indicate no increase of OI for the cured novolac copolymers, whereas the increase is observed for the cured resol copolymers. The activation energy for the thermooxidative degradation of the cured novolacs is about 12–15 kJ/mol lower as compared to that of the curd resols.
The use of extensional rheometry to establish operating parameters for stretching processes
Authors: Pearson Glen H. , Connelly Richard W. 
Published: April 2003

AbstractThis work describes a method of determining the limits of uniform extensibility, in terms of failure and fracture, from rheological tests in extensional flow. The limit of uniform stretching can be expressed in terms of the Weissenberg number for the process, as demonstrated by data for three chemically diverse polymers, polystyrene, poly(methyl methacrylate), and a polyester. The BKZ‐K model can be used to predict necking failure, as determined by the Considére criterion, and an empirical correlation can be derived for fracture.
Water‐swelling behavior of an ethylene–vinyl alcohol copolymer in the presence of sorbed sodium chloride
Authors: Apicella A. , Hopfenberg H. B. 
Published: April 2003

AbstractThe swelling behavior of water in a poly(ethylene–vinyl alcohol) copolymer (70 mol % vinyl alcohol) has been characterized at 25°C by vapor and liquid sorption experiments over a range of water activities. The activity of the vapor phase has been varied by incrementing the pressure of the water vapor in the sorption cell. Alternatively, for the liquid phase experiments, aqueous sodium chloride solutions of different concentrations have been used to vary systematically the activity of the water in the salt solution and to introduce various concentrations of salt into the copolymer films. Relaxation‐controlled sorption and Fickian diffusion have been observed as limiting cases of the water sorption behavior at high and low water activities, respectively. The effects of sorbed sodium chloride on water vapor sorption kinetics and equilibria were determined independently. A second salt phase forms within the previously homogeneous and seemingly single phase polymeric system, upon contacting the salt‐loaded film with a water vapor activity above a threshold value corresponding to the activity of water in the salt solution used to introduce the salt into the films. The water and salt solubilities in the ethylene–vinyl alcohol copolymer have been measured systematically to describe the complex sorption equilibria associated with this three‐component, multiphase system.
Polymerization of allyl methacrylate with wool fabric using different initiators
Authors: Abdel‐Hay F. I. , Khalil M. I. , Hebeish A. 
Published: April 2003

AbstractPolymerization of allyl methacrylate (AMA) with wool fabrics using different initiators, namely, potassium persulphate, Fe2+H2O2, benzoyl peroxide, ceric ammonium nitrate, and vanadium pentanitrate, was investigated. The percent of polymer add‐on depends upon the type and concentration of the initiator. Addition of metallic salts such as Fe3+ to the polymerization system enhances polymerization significantly when benzoyl peroxide and potassium persulphate are used independently as initiator. The opposite holds true for ceric ammonium nitrate and vanadium pentanitrate. With Fe2+H2O2, on the other hand, the enhancement is marginal. Also studied was the incorporation of Li+, Cu++, and Fe3+ at different concentrations in AMA—wool–benzoyl peroxide polymerization systems. Determination of the polymer add‐on on the basis of double bond analysis revealed that the remained double bond is governed by the magnitude of the polymer add‐on as well as by the type of initiator.
Directional permeability of asymmetrically oxidized poly(L‐methionine) film to oxygen dissolved in water
Authors: Aiba Sei‐Ichi , Minoura Norihiko , Fujiwara Yukihiko 
Published: April 2003

AbstractThe permeability of an asymmetrically oxidized poly(L‐methionine) film to oxygen dissolved in water was examined. It was recognized that the permeability along an increasing gradient of oxidized methionine composition is higher than the gradient is reversed. A qualitative analysis of this result was presented in terms of the oxygen solubilities into the film and water absorbed in the film.