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  • 1
    Electronic Resource
    Electronic Resource
    Radiation crosslinking of polymethylhydrogensiloxane containing methoxy groups (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 1821-1827 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bulk viscosity of polymethylhydrogensiloxane containing methoxy groups (PMHS-A) was measured before and after irradiation. The gel point was then determined from the variation of viscosity by irradiation by comparing it with methoxy-free polymethylhydrogensiloxane (PMHS-B) and polydimethylsiloxane blocked by methoxyldimethylsilyl (PDMS-C) or trimethylsilyl (PDMS-D). The following results were obtained: (1) The G value of crosslinking by irradiation is 167, 52, 25, and 3 for PMHS-A, PMHS-B, PDMS-C, and PDMS-D, respectively. (2) The scission of the SiO—CH3 bond is easier than that of the Si—H, Si—CH3, or SiCH2—H bond. The SiO—CH3 bond is PMHS-A is severed from SiO· and ·CH3 to induce chain reactions at the initial stage by irradiation. (3) It was confirmed that the commercial PMHS is at present free of methoxy groups. To replace the hydrogen of Si—H in the commercial PMHS with methoxy groups heat treatment with methanol was performed by which the G value of crosslinking was increased.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170624
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  • 2
    Electronic Resource
    Electronic Resource
    Radiation-induced grafting in the polyethylene-styrene system and differential thermal analysis of the grafted samples (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 3181-3192 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The graft polymerization of styrene onto high-density polyethylene films was carried out by γ-irradiation in the vapor phase. Two methods were used for grafting in these experiments: a preirradiation method and a simultaneous irradiation method. The effects of these grafting methods on the reaction mechanism of grafting and on the properties of the grafted samples were investigated. The amounts of styrene homopolymer in the grafted samples is under 2% in the case of the preirradiation method and above 10% in the case of the simultaneous irradiation method. The activation energies were calculated to be 18 kcal/mole for grafting in the preirradiation method and 15 kcal/mole for weight increase of polyethylene films in styrene vapor. The difference in the dimensional expansion between in the direction of stretching and the direction prependicular to it is smaller with preirradiation grafting than with grafting by the simultaneous irradiation method. Differential thermal analysis of the grafted films shows an endothermic peak due thermal decomposition which decreases gradually from 450°C to 415°C with increase in degree of grafting from 30 to 60%. The lowering of this peak temperature appears at a lower degree of grafting when the preirradiation method is used. On the basis of these results, it is concluded that the reaction rate of radiation-induced grafting in the vapor phase depends closely upon the processes of adsorption, dissolution, and diffusion of styrene monomer in polyethylene films; in the case of simultaneous irradiation method, the reaction proceeds comparatively uniformly in the amorphous region, while in the case of the preirradiation method, the reaction proceeds mainly at the boundary of the crystalline and amorphous regions.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.170111212
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetic approach to radiation-induced grafting in the polyethylene-styrene system (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 2729-2739 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To investigate the mechanism of radiation-induced grafting in this system, the increase of monomer concentration in the polyethylene film in styrene vapor was evaluated by measuring the weight increase and formulated to be V([M∞] - [M]). The decay of radical concentration was also measured by ESR and the rate constant of the decay was determined. The alkyl type radical was affected only a little by styrene, while the allyl type radical was much affected by styrene. A new computer investigation method was proposed to clarify the reaction mechanism. The data obtained were substituted into differential equations and used to calculate the pattern of increase of the degree of grafting for the preirradiation method with reaction in the vapor phase. Results of these calculations suggest that only allyl type radicals induce grafting reactions and that the grafting reaction seldom occurs in the region of grafted polystyrene.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.170121203
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  • 4
    Electronic Resource
    Electronic Resource
    The activation energy of radiation-induced grafting reaction in the polyethylene-styrene system (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 13 (1975), S. 299-301 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.130130510
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of divinylsulfone on the irradiation crosslinking of polypropylene (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2465-2473 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polypropylene films were irradiated with 60Co γ-rays in divinylsulfone (DVS) or butadiene (BD) gases. The variations of the intrinsic viscosities of the samples irradiated in vacuum or in DVS with dose showed usual patterns but the variation of the latter was somewhat more rapid. The intrinsic viscosity of the sample irradiated in BD could not be measured due to the early appearance of gel. The gel fraction of the sample irradiated in DVS appeared at lower dose than that irradiated in vacuum, but the former did not increase as much as the latter. The gel fraction of the sample irradiated in BD increased remarkably. The concentrations of the two kinds of double bonds increased in the sample irradiated in BD but levelled off gradually with dose. ESR study showed that the polypropylene radical reacted with DVS to form anisotropic radicals. The mechanisms of the effects of both reagents on irradiation of polypropylene were discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260917
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  • 6
    Electronic Resource
    Electronic Resource
    Radiation-induced reaction of ethylene-cyclohexane-carbon tetrachloride system (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 2901-2914 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The γ-ray-induced reaction of ethylene with carbon tetrachloride in cyclohexane was carried under a pressure of 30 kg/cm2 and at a temperature of 20°C. The liquid and the solid products were obtained. Their structures were discussed on the basis of infrared absorption spectra and differential thermal analysis curves. The liquid product is considered to be ethylene-carbon tetrachloride telomer. The solid product consists of three components, differing slightly in molecular structure and molecular weight. To clarify the reaction process, some runs with the ethylene-cyclohexane-(ethylene-carbon tetrachloride telomer) system were also carried out. In this system, only solid product was obtained. Thus, it is concluded that the reaction proceeds stepwise, the first step being the telomerization reaction and the second the graft polymerization of ethylene onto the telomer produced in the first step.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150091012
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