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  • Physics  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Kinetic study of preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 597-604 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene-perfluorovinyl ether) (PFA) film. The effect of grafting conditions was investigated. The dependences of the grafting rate on preirradiation dose and monomer concentration was found to be of the order of 0.5 and 1.3, respectively. The final degree of grafting was found to increase with dose and monomer concentration. However, it decreases as the grafting temperature increase. The overall activation energy for the graft polymerization was calculated from Arrhenius plots to be 5.6 kcal/mol. The activation energy for this grafting system was found to be independent of preirradiation dose used in the range from 10 to 100 kGy. The relationship between the grafting rate and film thickness gave a negative first-order dependence. The results suggest that the grafting proceeds by radical mechanism with bimolecular termination of growing chain radicals. It was reasonable concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220309
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  • 2
    Electronic Resource
    Electronic Resource
    Radiation-induced copolymerization of vinylene carbonate with methyl trifluoroacrylate (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3417-3421 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymerization of vinylene carbonate (VCA) with methyl trifluoroacrylate (MTFA) was carried out by gamma rays from 60Co at dose rates of 1 × 105 rad/h to 1 × 106 rad/h, temperatures of 0°C to 75°C, and molar ratios MTFA/VCA of 30/70 to 90/10 in the monomer mixture. By irradiation, VCA reacted with MTFA to give a white powder copolymer with low molecular weight. The copolymerization rate has a maximum at a concentration of 70 mol % VCA, and is proportional to the 0.92 power of dose rate. The apparent activation energy was 1.3 kcal/mol. Equimolar copolymer was obtained at molar ratio MTFA/VCA of 50/50 to 10/90. The reactivity ratios of both monomers, VCA and MTFA, were determined to be r(VCA) = 0.3 and r(MTFA) = 0.07, respectively.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221157
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Radiation-induced postpolymerization of trioxane in the solid state. V. Studies on copolymer composition (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 1883-1893 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the composition of copolymers obtained by the radiation-induced solid-state postpolymerization of trioxane with 1,3-dioxolane have been carried out. Gas-chromatographic analysis of the reaction mixtures showed that most of the 1,3-dioxolane disappears rapidly from the reaction system in an early stage of polymerization, and that the fraction of ethylene oxide units in the copolymer chain [E] decreases markedly with increasing polymer yield. This finding was confirmed by NMR spectra of the copolymer. DSC thermograms of the copolymer indicated that the relationship between the melting point and the average composition of copolymers prepared in this study differed from that found for copolymers in which comonomer units are distributed statistically in the polymer chain. It was suggested that the copolymer formed by the radiation-induced solid-state postpolymerization of trioxane-1,3-dioxolane is characterized by a heterogeneous distribution of ethylene oxide units in the copolymer chain. It was also found that, in the radiation-induced solid-state postpolymerization of trioxane-1,3-dioxolane, the amount of tetraoxane formation increased linearly with increasing polymer yield. Although it is extremely small compared with that obtained in solution polymerization, it is slightly larger in the trioxane-1,3-dioxolane system than in the trioxane system.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.150100701
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  • 4
    Electronic Resource
    Electronic Resource
    Radiation-induced postpolymerization of trioxane in the solid state. II. Kinetic study of radiation-induced postpolymerization of trioxane in dry and high-vacuum systemFor Part I, see Sakamoto et al.1 (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 8 (1970), S. 3061-3077 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study of the radiation-induced postpolymerization of trioxane in the solid state has been made. Trioxane was purified by sublimation through Ag2O and Na-K alloy in vacuo and was both irradiated and polymerized in a super-dry system under high vacuum. In the present study it was found that the initial rate of polymerization is larger than that reported previously. It is reasonably suggested that the postpolymerization of trioxane consists of two stages, i.e., a very large rate at the first stage and a relatively small one at the second stage. By using the kinetic scheme proposed previously kinetic parameters at the second stage were determined. It was found that trioxane can be postpolymerized even at a temperature below 30°C with good reproducibility and that the overall activation energy of the polymerization was less than 15 kcal/mole. No chain-transfer reaction seems to occur except at low temperatures. These results have been discussed in comparison with data reported previously.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.150081103
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  • 5
    Electronic Resource
    Electronic Resource
    Radiation-induced postpolymerization of trioxane in the solid state. IV. Copolymerization of trioxane with dioxolane (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 751-762 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radiation-induced postpolymerization of trioxane with 1,3-dioxolane has been investigated. Trioxane and 1,3-dioxolane were carefully purified in a rigorously dry, high-vacuum system. In the present study it was found that trioxane can be easily copolymerized with 1,3-dioxolane to give a copolymer having high molecular weight and excellent thermal stability. Typically, the isothermal weight loss after heating for 60 minutes under nitrogen at 222°C was 3.5% for a copolymer of trioxane and 1.0 wt-%1,3-dioxolane preirradiated with a dose of 1.0 × 105 Rad. The thermal stability of the copolymer was scarcely affected by the polymerization temperature and time, although it decreased slightly with increasing preirradiation dose. The dependences of the yield and inherent viscosity of the polymer on the preirradiation dosage, polymerization temperature and time were quite similar to those found for the homopolymerization of trioxane. The results were analyzed by using the kinetic scheme previously reported, and it was found that no chain transfer reaction occurs in this system. These results are discussed in comparison with those of homopolymerization reported previously.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.150100311
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  • 6
    Electronic Resource
    Electronic Resource
    Radiation-induced postpolymerization of trioxane in the solid state. III. Effect of oxygen on the postpolymerization of trioxane (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 2511-2521 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to investigate the effects of oxygen on the radiation-induced postpolymerization of trioxane in the solid state, a kinetic study has been made. Trioxane was purified by sublimation through Ag2O and Na-K alloy in vacuo and was irradiated and polymerized in the presence of rigorously dry oxygen. It was found that the initial rate of polymerization and the polymer yields are larger than those obtained in vacuo. By using the kinetic scheme proposed previously the results were analyzed kinetically. It was found that the influence of oxygen on the postpolymerization of trioxane is mainly attributable to the increase in the concentration of active species. The results obtained in dry air have been discussed in comparison with those in vacuo reported previously.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150090908
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