bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaction of poly(vinyl chloride) with magnesium and grignard reagents
Authors: Minoura Yuji , Hironaka Hisashi , Kasabo Toshiyuki , Ueno Yukio 
Published: April 2003

AbstractReaction of poly(vinyl chloride) with magnesium under various conditions was attempted, but poly(vinyl chloride) did not react with magnesium. The reactions of poly(vinyl chloride) with benzylmagnesium chloride and allylmagnesium chloride as Grignard reagents were carried out in tetrahydrofuran at reflux temperature. It was found that the chlorine atoms in the poly(vinyl chloride) were replaced by benzyl and allyl groups by the coupling reaction, and a small amount of Grignard reagent of poly(vinyl chloride) was formed by the magnesium–halogen exchange reaction. The extent of the substitution increased with increasing reaction time and concentration of the Grignard reagent.
Metal‐containing initiator systems. V. Radical and cationic polymerizations with initiator systems of reduced nickel and chlorosilanes
Authors: Otsu Takayuki , Aoki Shuzo , Nishimura Masato , Yamaguchi Masami , Kusuki Yoshihiro 
Published: April 2003

AbstractThe polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH3)nSiCl4−n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl4 > CH3SiCl3 > (CH3)2SiCl2 > (CH3)3SiCl ≃ 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH3)3SiCl > (CH3)2SiCl2 > CH3SiCl3 ≃ SiCl4. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed.
Heterogeneous copolymerization of acrylamide with maleic acid in dioxane
Authors: Myagchenkov V. A. , Kurenkov V. F. 
Published: April 2003

AbstractHeterogeneous copolymerization of acrylamide with maleic acid has been investigated. The process was carried out at 70°C in 1,4‐dioxane. The polarographic method of analysis was applied. The analysis of the experimental and theoretical composition distribution curves has shown an anomalously large composition polydispersion for the experimental distribution curves. This is attributed to the heterogeneity of the copolymerization process.
Copolymerization of trialkylvinylgermane
Authors: Minoura Yuji , Sakanaka Yasuhiro 
Published: April 2003

AbstractThe polymerization of trimethylvinylgermane (TMGeV) with the use of γ‐ray, radical, and ionic initiator was attempted, but homopolymer was not obtained. This monomer did not undergo polymerization by itself, but polymerized with high concentration of n‐BuLi. Copolymerization of TMGeV with styrene (St) and methyl methacrylate (MMA) was carried out by using radical initiator. From the results obtained by the copolymerization, monomer reactivity ratios and Q–e values were obtained as follows: for the system St(M1)–TMGeV (M2), r1 = 24.4, r2 = 0.009, Q2, = 0.0049, e2 = 0.43; for the system MMA (M1)–TMGeV (M2), r1 = 19.98, r2 = 0.05; Q2 = 0.037, e2 = 0.43., The polymerizability of TMGeV is discussed on the basis of the Q and e values obtained.
Decomposition of peroxycarbamates and their initiation of vinyl polymerization
Authors: Baines F. C. , Grezlak J. H. , Tobolsky A. V. 
Published: April 2003

AbstractA review is given of the synthesis, physical properties, and decomposition kinetics of organic peroxycarbamates. The activity of these compounds in initiating free‐radical vinyl polymerization is discussed. The decomposition of hexamethylene N,N′‐bis‐(α‐cumyl peroxycarbamate) has been measured in different solvents between 65 and 95°C and found to be a first‐order reaction governed by the specific rate constant kd = 2.21 × 1016 exp {−34 100/RT}. The initiator exhibits normal free‐radical polymerization kinetics and in polymerization of styrene at 80°C shows an initiating efficiency of 0.53. Cobalt naphthenate can act as both accelerator and retarder of styrene polymerization, depending upon its concentration and the temperature of the polymerization.
Vapor‐phase graft copolymerization of vinyl chloride and vinylidene chloride onto polypropylene fibers by simultaneous irradiation technique
Authors: Kawase Kaoru , Hayakawa Kiyoshi 
Published: April 2003

AbstractThe vapor‐phase graft copolymerization of vinyl chloride and vinylidene chloride onto polypropylene fibers was studied by a simultaneous γ‐irradiation technique. The weight increase during irradiation due to the grafting in monomers at constant vapor pressure was measured by a sensitive spring balance. The sorption of both monomers onto unirradiated polypropylene fibers was also measured. The graft copolymerization reaction was suppressed with increasing irradiation temperature, and the overall activation energies of grafting were negative in both monomers, −2.4 kcal/mole for vinyl chloride and −6.3 kcal/mole for vinylidene chloride. The initial rate of grafting increased linearly with the vapor pressure of monomers. The above dependence was found to parallel the sorption of monomers on polypropylene fibers. The reaction rates were proportional to the 0.9 power of the dose rate in both monomers. The relationship between the grafting and the sorption of monomers was discussed on the basis of kinetics.
Photodecomposition of polymethylsiloxane
Authors: Delman Alvin D. , Landy Milton , Simms Bernard B. 
Published: April 2003

AbstractInfrared spectroscopy studies were undertaken to determine the effects of ultraviolet light radiation on a methylsiloxane resin. The results indicate that SiCH2Si linkages were formed as a result of irradiation at wavelengths above 281 mμ from a xenon are lamp; on the other hand, SiOH and SiCH2CH2Si linkages were formed instead when the resin was exposed to the lower wavelengths emitted from a mercury vapor lamp. The different effects on the resin induced by the two ultraviolet light sources are attributed to the fact that only the energies from the mercury vapor lamp radiation are sufficient to cause the excitation of oxygen molecules in the air surrounding the irradiated polymer. The excited oxygen molecules prevented the formation of SiCH2Si structures by interacting with active %tbond;Si units that were formed as a result of SiC bond rupture to produce SiOH; SiCH2CH2Si linkages were formed as the result of a secondary reaction.
Phenylated polyquinoxalines from bis(phenylglyoxaloyl)benzene
Authors: Wrasidlo W. , Augl J. M. 
Published: April 2003

AbstractPhenyl‐substituted polyquinoxalines of unusually high oxidative‐thermal stability were prepared by one‐step solution condensations of aromatic tetraamines with 1,4‐bis‐(phenylglyoxaloyl)benzene and 1,3‐bis(phenylglyoxaloyl)benzene. The final polymers thus obtained show exceptionally good solubility in a variety of common organic solvents, such as chloroform, tetrachloroethane, dichlorobenzenes, and certain phenols. Polymerizations in these solvents lead to polyquinoxalines of high molecular weight at reaction rates which depend upon the solvent used. The phenylated polyquinoxalines exhibited glass transition temperatures between 253 and 317°C and polymer decomposition temperatures between 515 and 540°C, depending upon structure. Isothermal decomposition at 400°C in air showed a strong dependency of weight loss on structure. Tough, flexible films were cast from solutions.
Morphology of polyethylene crystals as polymerized by γ‐radiation
Authors: Toyota Nobuhiro , Machi Sueo 
Published: April 2003

AbstractThe morphology of polyethylenes formed upon polymerization by γ‐radiation below the melting point in various reaction media was investigated by using electron microscopy and scanning electron microscopy. When the polymerization was carried out in bulk at 30°C and in methanol, the polymer was fibrillar, and a small‐angle x‐ray scattering curve of the polymer did not indicate the existence of a long period. This suggests that the chains in the crystals have an extended conformation. When the polymerization was carried out in the presence of xylene at 30°C, platelet crystals having a folded structure were obtained. It was thus shown that the morphology of the growing polymer crystals is very much affected by the solubility of the polymer in the reaction medium. The effect of stirring during polymerization on the crystalline morphology was also studied.
Cyclic stress–strain behavior of the dry polycarbonate craze
Authors: Kambour R. P. , Kopp R. W. 
Published: April 2003

AbstractEquipment and methods have been developed which allow photomicrographic determination of the stress–strain properties of the individual craze. Serial cyclic tensile tests on polycarbonate crazes are described. Under stress the typical dry polycarbonate craze thickens solely by straining; no adjacent polymer of normal density is converted to craze material. The craze exhibits a yield stress followed by a recoverable flow to roughly 40–50% strain at 6000–8000 psi. On return to zero stress the craze exhibits creep recovery at a decelerating rate. The yield stress and loss factor of each cycle decrease with increasing initial strain and cycles initiating at 50% strain or more show completely Hookean behavior. Creep recovery results in recovery of yield stress and loss factor also. Craze tensile behavior is suggested to be essentially an extension of the craze formation process. Decrease in elastic modulus and yield stress with increasing strain are rationalized in terms of strain‐produced decrease in density and resultant increase in stress concentration factor on the microscopic polymer elements of the craze. Polymer surface tension and the large internal specific surface area of the craze are suggested to be important factors in the large creep recovery rates of the craze.
Grüneisen constant and thermal properties of crystalline and glassy polymers
Authors: Wada Yasaku , Itani Akira , Nishi Toshio , Nagai Satoshi 
Published: April 2003

AbstractPolymer crystals are characterized by strong anisotropy of binding forces among units, i.e., the intrachain force constant f is much larger than the interchain force constant g. The anisotropic lattice is reduced to an isotropic one, in which each lattice point represents N* units (segment) along the chain axis of the anisotropic lattice [N = 2(f/g)1/2]. Vibrational modes of the reduced lattice correspond to interchain modes of the original lattice, i.e., modes whose frequencies are governed by interchain potential. Anharmonicity of crystalline force field is assumed to be related predominantly with interchain force alone. Thermodynamic and transport equations for a simple lattice are applied to the reduced, isotropic lattice, and numerical results are obtained for high‐density polyethylene. The Grüneisen constant γ was obtained from the pressure dependence of sound velocity. The heat capacity of the reduced lattice, Cinter (interchain specific heat), was calculated from Grüneisen's equation, α = γβCinter (where α = thermal expansion coefficient, β = compressibility), and the mass of a segment m* was estimated from Dulong‐Petit's equation, Cinter = 3ρk/m* (where ρ = density, k = Boltzmann constant). The value of m* is consistent with N* from force constants, m* = N*m (where m = mass of a unit in the original lattice). m*θ3 (where θ denotes the Debye temperature of the reduced lattice) is calculated from low temperature specific heat. The value of m* calculated from m*θ3 and θ from other sources agrees with that from the estimate by Dulong‐Petit's equation. The high‐temperature thermal conductivity K was calculated through Leibfried‐Schloemann's equation by employing γ and m*θ3 as estimated as described above; satisfactory agreement was obtained with experiment. Poly(methyl methacrylate) and polystyrene were also studied by similar methods.
Intrinsic viscosities of polymers in mixed solvents
Authors: Dondos A. , Patterson D. 
Published: April 2003

AbstractThe intrinsic viscosity of a polymer in a solvent mixture is related to the excess free energy of the solvents. Intrinsic viscosities at different temperatures are obtained for poly‐2‐vinylpyridine–chloroform–ethyl alcohol, poly(methyl methacrylate)–chloroform–ethyl alcohol, polystyrene–cyclohexane–benzene, polystyrene–dioxane–chloroform, and polystyrene–cyclohexane–ethanol. Qualitative, but not quantitative, agreement is found between theory and experiment.
Compressibility of polymers
Authors: Haward R. N. 
Published: April 2003

AbstractThe compressibility of polyisobutylene and polystyrene above their glass transition temperature is treated as the sum of two parts; a free‐volume compressibility and, as originally suggested by Bridgman, a compressibility of the molecules themselves. Two different models are used to treat the free‐volume compressibility, and as a result values for the molecular compressibility are estimated. These are in reasonable agreement with other values in the literature. The magnitude of this “molecular compressibility” is then considered in relation to some existing treatments of intermolecular forces. These suggest that intermolecular contacts are more compressible than covalent bonds, and on this basis the observed levels of molecular compressibility can be explained.
Effect of birefringence on low‐angle light‐scattering patterns from oriented polymer films
Authors: Stein R. S. , Erhardt P. F. , Chu W. 
Published: April 2003

AbstractThe effect of birefringence of a polymer film upon its photographic light‐scattering pattern is considered for the case of a single, anisotropic, two‐dimensional spherulite imbedded in a birefringent matrix. It is shown that for the case of a polarizer and analyzer crossed at +45° and −45° to the analyzer, the scattering pattern is modified in a manner agreeing with experimental observation.
Effect of birefringence on the scattering of light
Authors: Legrand D. G. 
Published: April 2003

AbstractThe effect of birefringence on light scattering is considered, using classical theory. It is shown that in conjunction with polarized light scattering, the use of birefringence can aid in the reduction of experimental errors; also how new checks on theory can be made. The treatment is applied to scattering from simple gaseous molecules and thin polymeric films.
Influence of superimposed steady shear flow on the dynamic properties of polyethylene melts
Authors: Kataoka Tadao , Ueda Shigeyuki 
Published: April 2003

AbstractExperiments in which an oscillatory shear flow is superimposed on a steady state shear flow were performed on polyethylene melts by the use of a cone and plate type rheogoniometer. The phase difference between oscillatory shear stress and shear strain increases in all cases and for all frequencies with the increase of the superimposed shear rate. Between ω0, the frequency at which the phase difference is π/2 and the steady shear rate \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma $\end{document}, as found by Booij for polymer solution, the relation ω0 = 1/2 \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma$\end{document}. holds also for polyethylene melts. The significance of this relation is discussed briefly from the viewpoint that the entanglement density decreases with the increase of the imposed shear rate.
Effects of orientation on dynamic shear behavior of some amorphous polymers from 4.2° to 300°K
Authors: Frosini V. , Woodward A. E. 
Published: April 2003

AbstractThe dynamic shear behavior of four highly amorphous polymers in the unstretched and stretched states (draw ratios 3:1 to 6:1) was investigated with a torsion pendulum at temperatures from 4.2°K to 180–300°K and frequencies from 0.4 to 3.2 cps. The polymers studied were polystyrene, poly(vinyl acetate), poly(vinyl propionate), and poly(isobutyl vinyl ether). Previously unreported loss maxima were found at 48°K (1.5 cps) and 149°K (1.3 cps) for poly(vinyl proplonate), at 10°K (1.0 cps) for poly(vinyl acetate) and at 9°K (1.6 cps) for poly(isobutyl vinyl ether). Uniaxial orientation increased the shear storage modulus G, measured with the torsion axis parallel to the stretch direction and caused changes in the loss peaks which depended on the polymer material studied.
Small‐angle x‐ray scattering from poly(tetramethyl‐p‐silphenylene) siloxane (TMPS) fractions
Authors: Pollack S. S. , Magill J. H. 
Published: April 2003

AbstractSmall‐angle x‐ray scattering studies were made on bulk‐crystallized samples and annealed oriented films of TMPS. The temperature dependence of the small‐angle scattering was determined over a range of annealing conditions. The effect of sample molecular weight on the small‐angle peaks was also studied. The peak intensity, measured at room temperature after annealing, was strongly dependent on the annealing conditions. The position of the peak gradually moved to smaller angles (largerdspacings) as the annealing temperature was raised. Surface free energies were deduced from the melting point dependence of the crystallite size. This surface energy was found to increase with molecular weight in accord with values deduced for spherulite growth rate‐temperature dependence.
Unperturbed dimensions of poly(ethylene oxide)
Authors: Beech D. R. , Booth C. 
Published: April 2003

AbstractThe intrinsic viscosities of fractions of poly(ethylene oxide) in the molecular weight range 1.5 × 103 to 106 have been measured at 25°C in benzene, carbon tetrachloride, and acetone; at 35°C in 0.45M aqueous potassium sulfate; and at 50°C in methyl isobutyl ketone and diethylene glycol diethyl ether. The latter three are practically theta solvents. The value of (r02/M)1/2 for poly(ethylene oxide) is calculated to be 0.84 Å from the molecular weights of the high molecular weight fractions, and their intrinsic viscosities in the theta solvents and acetone. Erroneous values result if the usual methods of determination are applied to the data obtained for the low molecular weight (<104) fractions or to the intrinsic viscosities in the very good solvents, benzene and carbon tetrachloride.
Glass transition temperatures of several fluorine‐containing polymers
Authors: Brown Daniel W. , Wall Leo A. 
Published: April 2003

AbstractThe glass transition temperatures Tg of several fluorine‐containing polymers were determined by use of the differential scanning calorimeter. Values between −3 and 230°C were obtained. In polymers of α‐olefins, Tg increases with the fluorine content of the backbone and the length of the n‐perfluoroalkyl branch. In styrene polymers Tg also is higher if the backbone contains fluorine but nearly the same Tg's are found for polymers with phenyl and pentafluorophenyl groups. Saturated polymers of perfluoro‐α,ω‐dienes have lower Tg's than polyperfluoro‐α‐olefins. The Tg's of chloroperfluoropolymers are higher than those of perfluoropolymers. Polyperfluoropentadiene‐1,3 has the lowest Tg of the polymers examined. Polyperfluoropentadiene‐1,3 forms by 1,4‐addition.
Styrene‐methyl acrylate copolymers and acrylate homopolymers in solution
Authors: Matsuda H. , Yamano K. , Inagaki H. 
Published: April 2003

AbstractMolecular weight determinations by light scattering and osmometry and intrinsic viscosity measurements were made in various solvents on fractions of styrene–methyl acrylate copolymers with different compositions and on acrylate homopolymers prepared by free‐radical reaction. Relations between intrinsic viscosity [η] and molecular weight M thus established are compared with those reported by other authors. 2‐Methylcyclohexanol was found to be a theta solvent for the copolymers and both parent homopolymers, and isoamyl acetate was a theta solvent for poly(methyl acrylate). From theta point viscosity data obtained with these solvents, unperturbed chain dimensions were estimated. The results are compared with the unperturbed dimensions estimated from the [η]–M relations obtained in good solvents. On the basis of the experimental data it was found that the unperturbed dimension depends linearly on the copolymer composition, in contrast to the case of styrene–methyl methacrylate copolymers. Composition dependences of the theta temperature and of the parameter describing the long‐range interactions between nonadjacent segments in polymer chains were investigated. The result implies that long‐range interactions between monomeric units never disappear even when those between the same monomeric units vanish. The Huggins constant for copolymer is discussed in terms of the excluded volume variable.
Effect of finite extensibility on the viscoelastic properties of a styrene–butadiene rubber vulcanizate in simple tensile deformations up to rupture
Authors: Smith Thor L. , Dickie Ray A. 
Published: April 2003

AbstractStress–strain and rupture data were determined on an unfilled styrene–butadiene vulcanizate at temperatures from −45 to 35°C and at extension rates from 0.0096 to 9.6 min−1. The data were represented by four functions: (1) the well‐known temperature function (shift factor) aT; (2) the constant strain rate modulus, F(t,T), reduced to temperature T0 and time t/aT, i.e., T0F(t/aT)/T; (3) the time‐dependent maximum extensibility, λm(t/aT); and (4) a function Ω(χ) where χ = (λ − 1)λm0/λm, in which λ is the extension ratio and λm0 is the maximum extensibility under equilibrium conditions. The constant strain rate modulus characterizes the stress–time response to a constant extension rate at small strains, within the range of linear response; λm is a material parameter needed to represent the response at large λ; and Ω(χ) represents the stress–strain curve of the material in a reference state of unit modulus and λm = λm. The shift factor aT was found to be sensibly independent of extension. At all values of t/aT for which the maximum extensibility is time‐independent, the relaxation rate was also found to be independent of λ. These observations indicate that the monomeric friction coefficient is strain‐independent over the ranges of T and λ covered in the present study. It was found that λm0 = 8.6 and that the largest extension ratio at break, (λb)max, is 7.3. Thus, rupture always occurs before the network is fully extended.
Lactone polymers. I. Glass transition temperature of poly‐ε‐caprolactone by means on compatible polymer mixtures
Authors: Koleske J. V. , Lundberg R. D. 
Published: April 2003

AbstractDynamic mechanical properties determined with a torsion pendulum were used to ascertain the glass transition temperature Tg of poly‐ε‐caprolactone. By measurements on compatible blends of poly‐ε‐caprolactone and poly(vinyl chloride), the Tg of amorphous poly‐ε‐caprolactone was shown to be 202°K at about 1 cps. This is 16°K lower than the Tg of annealed, crystalline polymer. The blend transition data were well fitted by both the Fox and the Gordon‐Taylor expressions. The Fox expression was also used to describe the decrease from 233°K of the secondary low‐temperature relaxation due to poly(vinyl chloride) by assuming the low temperature relaxation of poly‐ε‐caprolactone, 138°K, was responsible for the decrease in the blends. The 138°K relaxation due to poly‐ε‐caprolactone was decreased when more than 50% poly(vinyl chloride) was present.