Radiation-Induced Cross-Linking of Polyethylene in the Presence of Various Acetylenic Compounds |
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| Authors: | Miyuki Hagiwara Tôru Tagawa Eishun Tsuchida Isao Shinohara Tsutomu Kagiya |
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| Institution: | 1. Japan Atomic Energy Research Institute Takasaki Radiation Chemistry Research Establishment , Watanuki-Machi, Takasaki, Gunma, Japan;2. Japan Atomic Energy Research Institute Takasaki Radiation Chemistry Research Establishment , Watanuki-Machi, Takasaki, Gunma, Japan;3. Department of Polymer Science , Waseda University , Nishiookubo, Shinjuku-ku, Tokyo, Japan;4. Faculty of Engineering , Kyoto University , Sakyo-ku, Kyoto, Japan |
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| Abstract: | A study was made on the radiation-induced cross-linking reaction of polyethylene by exposing film samples to ddot]Co γ-rays in vacuum or in the presence of various acetylenic compounds such as acetylene, its C3 to C5 higher derivatives, and their mixture with tetrafluoroethylene (TFE). The samples (0.2 mm thick) were found to decrease in weight when irradiated in vacuum, but to increase in the presence of the additives. The IR spectrum measurements of the resultant showed that the trans-vinylene unsaturation increased by the irradiation, especially in the presence of the C3 to C5 derivatives, and terminal vinyl increased markedly in acetylene. However, the formation of these unsaturations were depressed when the film was irradiated in the mixed gas with TFE. The rate of the cross-linking reaction was accelerated by the addition of acetylene-TFE, acetylene, trifluoromethyl-acetylene, perfluorobutyne-2, perfluorobutyne-2-TFE, and methylacetylene-TFE G(cross-linking) = 4.4-1.2]. It was reduced with methylacetylene, butyne-1, butyne-1-TFE, pentyne-1, pentyne-1-TFE, pentyne-2, pentyne-2-TFE, G(cross-linking) = 0.6-0.1]. On the basis of these experimental results a chain reaction scheme of the cross-linking is proposed, and it is discussed on the basis of the activation energy of the elementary reactions. |
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