bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the γ‐irradiation of natural rubber latex
Authors: Minoura Yuji , Asao Mamoru 
Published: April 2003

AbstractVulcanized latex was obtained by the γ‐irradiation of natural rubber latex. The optimum cure was attained with ca. 2 × 107 r, in the case of 40% latex. Owing to the acceleration action of the water present, rubber in latex crosslinked more easily than it did in previously dried latex film, but no appreciable difference was found between the crosslinking in latices of various water contents. The protein in the latex deteriorated under γ‐irradiation, but the properties of the latex were not damaged. The maximum tensile strength of the film obtained by drying this irradiated latex was larger than that of solid rubber irradiated in air; this may correspond to the fact that the irradiation, even when carried out in air, brought about no side reactions such as oxidation, etc., of rubber in latex. The aging behavior of the irradiated film was quite superior, the tensile strength being greater after aging than before.
Radiation crosslinking of vinyl chloride–vinyl stearate copolymer
Authors: Miller A. A. 
Published: April 2003

AbstractThe crosslinking of internally plasticized polyvinyl chloride–stearate copolymer by irradiation with high‐energy electrons was studied. Based on gel yields and swelling as a measure of relative crosslinking, the effect of added tetra‐functional monomers, and of carbon black and silica fillers are discussed. Crosslinking by dicumyl peroxide a t 170°C. even in the presence of a stabilizer, causes concurrent decomposition (dehydrochlorination) which is avoided in the radiation‐crosslinking process. The heat stability of the copolymer is not impaired by radiation crosslinking under the proper conditions. Results of tensile measurements a t 25 and 150°C. are given for the radiation‐crosslinked copolymer with and without filler reinforcement.
Studies on the γ‐irradiation of natural rubber latex. The effects of organic halogen compounds on crosslinking by γ‐irradiation
Authors: Minoura Yuji , Asao Mamoru 
Published: April 2003

AbstractAs the accelerating effect of water in the crosslinking reaction of rubber in natural latex by γ‐irradiation was assumed to stem from the decomposition of water into radicals by γ‐irradiation, more effective reagents were sought among the organic halides which have greater G values for radical formation by γ‐irradiation and, simultaneously, an affinity for rubber greater than that of water. 1,2‐Dichloroethane, chloroform, carbon tetrachloride, and benzene (for comparison) were tested, and these compounds, except for benzene, were found to accelerate the reaction in proportion to their G values for radical formation. Benzene was found to have no effect, in concentrations between 1 and 5 phr. The optimum dosage was decreased to 2.1 × 106, 1.0 × 106, and 7.6 × 105 r by the addition of 1, 3, and 5 phr of carbon tetrachloride, respectively, and was assumed to have decreased to 1.17 × 107, 9.0 × 106, and 7.6 × 106 r with 1, 3, and 5 phr of 1,2‐dichloroethane, and to 8.6 × 106, 6.2 × 106, and 5.2 × 106 r with 1, 3, and 5 phr of chloroform, respectively. The physical properties of the films obtained at the optimum dosages under these accelerating conditions were equal to those of the latex irradiated up to the optimum dosage with no addition of halide. No side reactions occurred during the halide‐accelerated crosslinking that were sufficiently extensive to influence the infrared spectra.
The mechanism of post cure of viton A Fluorocarbon elastomer
Authors: Smith J. F. , Perkins G. T. 
Published: April 2003

AbstractThe necessity for oven post‐curing Viton A vulcanizates is explained in the following way: The formation of crosslinks is accompanied by the elimination of HF from the polymer. In the subsequent reaction of HF with the magnesium oxide present as acid acceptor water is formed which acts to inhibit the full development of cure unless it is removed from the vicinity of the polymer by post‐curing in an open system. Measurement of the rate of elimination of water from the polymer serves as a method of following the development of crosslinking during cure. Approximately two moles of water, derived from four moles of hydrogen fluoride, are associated with the use of one mole of diamine curing agent. This ratio is confirmed by independent estimates of the relationship of crosslinking density to curing agent level based on measurements of swollen compression moduli.
Studies on straining of amorphous polyethylene terephthalate above the glass temperature
Authors: Kawaguchi T. 
Published: April 2003

AbstractA viscoelastic theory based on a simple model is developed to describe the stress–strain relation of amorphous plastics above the glass temperature. One of the bases of the theory is that the stress is proportional to the number of molecular chains traversing a unit cross section. Experimental results for the stress–strain relation of amorphous polyethylene terephthalate in the range 80–120°C. are presented. These are shown to agree with the theory within the experimental error.
The effects of sodium salts on the additive in viscose regeneration process
Authors: Levine M. , Burroughs R. H. 
Published: April 2003

AbstractVarious chemical additives are commonly used in viscose to reduce the swelling of the resultant fibers and films. It was found that inorganic sodium salts, introduced into the additive‐containing viscose, alter the action of the additive. The following salts, listed in order of the values of gel swelling ratios obtained with them, interfere with the deswelling of the viscose during regeneration: citrate > thiosulfate > tartrate > sulfate > chloride = phosphate = thiocyanate > acetate > nitrate > control. Sodium idodide did not affect the usual deswelling of the films, and sodium sulfide and sodium carbonate caused the films to deswell slightly more than the control sample. It was proposed that the effectiveness of the salts follows a Hofmeister or lyotropic series.
Crosslinking of cotton cellulose with diglycidyl ether
Authors: Jones Eugene W. , Rayburn James A. 
Published: April 2003

AbstractCertain diepoxides react with cellulose under a variety of conditions to give covalent crosslinks. The ether linkages formed with diepoxides are stable to hydrolysis and offer advantages over crosslinks formed with N‐methylol compounds. Diglycidyl ether (DGE) has many advantages over other diepoxides. It has a high epoxide equivalent, low vapor pressure, and is completely water‐soluble. Both epoxide groups have equal reactivity and their reaction with cellulose can be catalyzed by acids or bases. Fabric properties obtained with DGE with the use of acidic and basic catalysts at various temperatures and concentrations are compared. DGE applied with acidic catalysts by the conventional pad‐dry‐cure process gave both dry and wet crease recovery. The same catalyst in a wet‐cure process promoted polymerization instead of crosslinking and resulted in only slight improvement in crease recovery, but did increase the tear strength. Under conventional conditions of drying and curing, weakly basic catalysts did not promote crosslinking. However, concentrations of sodium hydroxide around 3% gave both dry and wet crease recovery. Strong concentrations of sodium hydroxide at room temperature or in a wet‐cure process promoted crosslinking and gave predominantly wet crease recovery.
The role of crosslinking in enhancing wet crease recovery of cellulosic fabrics
Authors: Tesoro Giulana C. 
Published: April 2003

AbstractConsiderable experimental evidence has been reported in recent years in support of the theory that covalent crosslinkages between cellulose chains are essential to impart dry crease recovery to cellulosic fabrics. It has been proposed also that wet crease recovery can be increased by simple substitution in the total absence of crosslinking. It is the purpose of this paper to report a direct comparison of the effects of monofunctional and bifunctional reagents of identical size and unequivocal functionality on the wet crease recovery and other properties of cotton, rayon and other regenerated cellulose fabrics. The compounds employed are derivatives of vinyl sulfones. The synthesis of these products is briefly described, with some emphasis on the new compounds and intermediates prepared. The procedure selected for reacting the sulfones with cellulosic fabrics is described, and the differences observed in the chemical behavior of the mono‐ and bifunctional compounds are discussed. A comparison of the physical properties, and particularly of the wet crease recovery of fabrics modified to the same extent with mono‐ and bifunctional reagents, suggests that side chains are ineffective in enhancing wet crease recovery of cellulosic fabrics. The increase in wet crease recovery resulting from the reaction of swollen cellulose with polyfunctional reagents must therefore be attributed to the formation of covalent crosslinks.
Methods for determining stress distribution in adherends and adhesives
Authors: Hahn K. F. , Fouser D. F. 
Published: April 2003

AbstractLoading a lap joint in tension causes the adherends to increase their tensile stress over the nominal because of the bending produced by the offset of the joint. Knowing the configuration of the joint and the tensile stress, the stress distribution in the adherends outside the joint can be determined. The theory, with resulting equations, is based on the assumption that the adherends act like a plate bent to a cylindrical surface. If the bending of the adherends is eliminated by the use of a double overlap joint, the stress distribution in the adhesive can be determined. This analysis is based on existing mathematical findings of the load distribution in riveted joints. The resulting equations have been proven experimentally by the use of the photo stress technique, and can be applied to adhesively bonded, soldered, brazed, welded, and under certain conditions, riveted joints.
Room‐temperature curing adhesives for structures
Authors: Dickstein J. , Blommers E. A. , Karo W. 
Published: April 2003

AbstractMethods by which synthetic adhesives can be cured at ambient temperatures are covered. The alkyl cyanoacrylates, epoxies, and MPL monomers can be cured, with little shrinkage, to obtain metal adhesive bonds which compare favorably to those obtained by high temperature modes of curing. An investigation by which novolac epoxies were rendered more flexible with accompanying increases in the temperature and salt spray resistance is described.
Characterizing impact behavior of thermoplastics
Authors: Wolstenholme W. E. 
Published: April 2003

AbstractConventional impact testing of thermoplastics gives a single numeric criterion of impact behavior in terms of total breaking energy. It is shown that impact behavior is characterized by an elastic phase and, after yielding, a plastic phase may occur. An autographic impact tester was built by modification of a standard pendulum hammer Izod impact unit. Force‐time impulse curves show three characteristic categories in breaking; catastrophic, plastic drawing with tearing, and tearing. Photographs of impulse curves on five commercial thermoplastics clearly depict the three breaking categories. The impulse as measured by the area under the force‐time curve shows a linear correlation with impact strength. The peak force at yielding exhibits over a 2 to 1 variation among the five commercial plastics. The three materials with highest impact strengths absorb approximately 70% of the total impulse after yielding. These results indicate that impact strength is not a good single measure of the mechanical behavior of the impact properties of thermoplastics.
A study of the compression fatigue and the damping phenomena of tire cord
Authors: Kemmnitz Güunter 
Published: April 2003

AbstractThe dynamical properties of tire yarns were investigated, the De Mattia method being used for compression fatigue and the Meskat‐Rosenberg‐Hoffmann instrument for the performance during an alternating tensile strength test. Various influences in the test of compression fatigue after De Mattia were investigated. The intensification of the test by increasing the flex angle leads to a considerable decline in tenacity. With increasing the ply twist, the residual strength shows a maximum which lies at an optimum of cord construction. The maximum of the residual strength follows from the increase of the static twist loss and the decrease of the compression fatigue according to the ply twist. The influence of dipping, temperature, and frequency as well as the properties of different cord types were examined. The correlation between tension and flexibility is shown during the alternating tensile strength test of raw cords assuming that both change sinusoidally. Equations for the calculation of the complex modulus, the Young modulus, and the viscosity modulus as well as of the specific damping and the loss energy are stated. Measurements were carried out with viscose improved and viscose super cords and some of the results compared to those for nylon cords. The damping shows in relation to the twist construction a minimum at a constant ply twist and at a certain cable twist which is represented by the ratio Vz of ply/cable twist. A comparison of the two dynamical test methods, i.e., the compression fatigue and the tensile strength test, shows that a maximum residual strength of a certain twist construction corresponds to a minimum in damping and in twist loss. So far there exists a correlation between the static and the two different dynamic tests. Finally, the results of the two dynamic test methods are compared with the properties of cords in the tire. This comparison shows that not even in one case do the results of the laboratory tests contradict the properties of cords in tires, but in most cases correspond to them. Therefore, it can be assumed that it is possible to investigate the dynamic properties of cord twists in tires by laboratory tests with both test methods, i.e., the compression fatigue after De Mattia and the loss energy with the Meskat‐Rosenberg‐Hoffmann instrument.
Morphology of thermally degraded polyethylene
Authors: Fujiwara Yasuna , Harada Kenyū 
Published: April 2003

AbstractAs a clue to the solution of the spherulite structure of polymers, dendrites of thermally degraded polyethylene crystallized from the melt were studied by optical and electron microscopy. The crystal habit of the dendrites was very special, resembling neither that found in polyethylene, which has much longer chains, nor that of paraffin wax which has considerably shorter chains. Electron microscopic observation revealed the existence of developed terraces about 100 A. in height, which is in accordance with the structure of polymer single crystals. The molecules appear to fold themselves into the lamellae on crystallizing from the melt.
The effect of carbon black on thermal antioxidants for polyethylene
Authors: Crompton T. R. 
Published: April 2003

AbstractThe presence of 2 to 3% of carbon black prevents photooxidation of polyethylene but affords only slight protection against thermal oxidation. Small quantities of amine or phenolic antioxidants are also added therefore to prevent thermal oxidation during processing. The influence of various types of carbon black on the decomposition of one particular amine antioxidant, N,N′‐di‐β‐naphthyl‐p‐phenylenediamine which occurs during milling with polyethylene has been studied in detail. Acidic channel blacks of small particle size have been shown to accelerate the oxidation of the antioxidant. Further degradation, or adsorption onto the carbon black, of this antioxidant also occurs. With the alkaline furnace blacks of large particle size, however, oxidation takes place only to the same extent as that which occurs in clear polyethylene.
The electrical properties of some crosslinked isophthalic polyesters
Authors: Tucker R. W. , Hastings C. C. 
Published: April 2003

AbstractThe a.c. electrical properties (dielectric constant and loss index) of several series of crosslinked isophthalic polyester resins were investigated over the frequency range 50 to 105 cycles/sec. and over the temperature range −60°C. to above the temperature for maximum loss index. In one series of these resins, the ratio of isophthalic acid to maleic anhydride was varied, in another the chain length of the diol was varied, and in another the concentration of styrene was varied. The temperatures at which the maximum values of the electrical properties occurred are shown to be related to the heat distortion temperature, and within the range of compositions studied, could be predicted from chemical structure. The data suggest that a ratio of isophthalic acid to maleic anhydride of less than 1 : 1, short‐chain diols, such as 1,2 propanediol, and more than 50% by weight of styrene will yield the best electrical properties in polyesters of the type studied.
Differential thermal analysis of high polymers. IV. Saturated linear polyesters
Authors: Ke Bacon 
Published: April 2003

AbstractGlass transition, cold crystallization, premelt crystallization, and melting in polyethylene terephthalate and copolyesters have been studied by differential thermal analysis. The transitions are affected by changing the chemical composition of the polyesters through replacing one monomer partially or completely with a different monomer. Quenching, annealing, and/or drawing, which render different degrees of crystallinity to a polyester, can also be detected directly from the thermograms.
Instrumentation for angular dependence measurements of light scattering
Authors: Dandliker W. B. , Schapiro Harriette 
Published: April 2003

AbstractA filtration‐type light scattering cell effectively sealed against contamination by a liquid trap and by a long helical impingement filter is described. Very low stray light levels are achieved by means of large cell diameter and a narrow light beam. Modifications in the Brice‐Phoenix light scattering instrument necessary for the proper application of the cell are discussed. The intensities and angular dependence for water observed in this cell are in very good agreement with those obtained after multiple distillation. The excess scattering curve for 3% phosphotungstic acid in 0.3M NaCl and 1M HCl is that of a Rayleigh scatterer in the range observed (25.8 to 135°).
Polymerization studies with allyl starch
Authors: Wilham C. A. , McGuire T. A. , Rudolphi A. S. , Mehltretter C. L. 
Published: April 2003

AbstractIndustrial evaluation of allyl starch as a coating material in the late 1940's established that properties such as brittleness, nonhomogeneity of product, solvent solubility, and poor water resistance limited its potentialities to specialty uses. Infrared absorption analysis of allyl dextrin coatings before and after curing established that 50% of the allyl groups oxidatively polymerized. Since some degradation occurs in this process, attempts were made to limit this degradation and to improve coating properties by polymerizing pendant allyl groups with free‐radical initiators. Homopolymerization studies involving effets of molecular size and dextrin concentration indicated that intra‐molecular polymerization dominated early stages of the reaction. Graft copolymerization of a few unsaturated monomers resulted in products containing 3.6% acrylonitrile, 8.5% acrylic acid, and 15–18% acrylamide. Only with the acrylamide did no concurrent homopolymerization of dextrin allyl groups occur. Neither variations in method for polymerizing the allyl dextrins nor use of copolymers was effective in producing suitably cured coatings.
The miscibility of polymers: Interaction parameter for polybutadiene with polystyrene
Authors: Paxton Thomas R. 
Published: April 2003

AbstractWe have measured the solubility of mixtures of polybutadiene and polystyrene in toluene, benzene, and carbon tetrachloride, using polymers of various molecular weights and mixed in various proportions. The equations developed by Maron for solutions of nonelectrolytes have been modified for three components and for solutions of low molecular weight polymers at high concentrations. The application of these equations has provided estimates of the polymer–polymer interaction parameters χ23. The polymer–solvent interaction parameters χ12 and χ13 apparently are functions of the concentration and are not readily obtained from the present limited data.
Theory of mechanical properties of fibrillar structures
Authors: Hearle J. W. S. 
Published: April 2003

AbstractA theory of the extension of a roughly oriented fibrillar structure is worked out. Two mechanisms are involved: an extension of the fibrils, and a bending of the fibrils with accompanying deformation of noncrystalline material lying between them. The combined equation for both mechanisms does not fit experimental results for nylon and ordinary rayon, but does fit results for high modulus (polynosic) rayons.
Effect of structure on temperature stability and solubility of polyester‐urethanes
Authors: Engel J. H. , Reegen S. L. , Weiss P. 
Published: April 2003

AbstractThe composition of crosslinked polyester–urethanes has been varied by adjusting the ratio of ester to urethane groups. The crosslinking density of these materials has been varied by changes in the polyester functionality. The polyester–urethanes have been subjected to solvent extraction, wherein it was found that at high crosslinking densities, the solubility of the polymers is unaffected by the ester‐urethane ratio. At low crosslinking densities, solubility increases slightly with increasing urethane concentration. The solubility was also found to increase with decreasing crosslinking density. Data obtained from isothermal heat aging and thermogravimetric analysis, both carried out in air and in inert atmosphere, indicate that thermal stability increases with increasing ester/urethane ratio and is independent of crosslinking density where the ester/urethane ratio is held constant. In addition, data obtained from heat aging and thermogravimetric analysis have indicated that decomposition of the samples occurs as rapidly in inert atmosphere as in air, indicating that the decomposition occurs chiefly by a nonoxidative mechanism.
Interferometric method for determining the distribution of graft concentration in radiation‐induced graft copolymer
Authors: Matsuo H. , Iino K. , Kondo M. 
Published: April 2003

AbstractMicrointerferometry was applied as a quantitative method for determining the transversal distribution of graft concentration instead of the usual determination of an overall graft concentration of the radiation‐induced polypropylene–styrene graft copolymer. Since polystyrene has a higher refractive index than polypropylene, the features of the interference fringe provide direct visualization of the distribution curve of graft concentration. The application of the method leads to clarify the effects of radiation dose rate, film thickness, monomer concentration, temperature, and grafting technique on the graft composition. A retardative effect on grafting appears in the vicinity of the surface, when the grafting is performed in lower radiation field and with thinner film. This is well explained by the variation in the grafting rate constant as a function of monomer concentration in the film. Furthermore, the post‐irradiation effect and accelerative effect of methanol were followed. They act effectively to form the surface, volumetric, and embedded grafts. The method has also proved useful in routine examination for a qualitative estimate of the graft copolymer.