Procuction of Polyacetylene from Polyethylene Induced by High Voltage Breakdown

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It was demonstrated that a new polyacetylene can be produced by a high voltage breakdown (HVB) of polyethylene (PE)together with a formation of primary alkyl radical.No unstable chemical species created by the breakdown of PE as insulator are reported in detail and characterized by means of ESR method up to date as far as we know. Therefore it is necessary to know what kind of unstable chemical species are produced during the breakdown and to study the mechanism of breakdown of PE from view point of not only basic science but also industrial application as typical insulating materials.A special sample tube and electric circuit for the breakdown of PE powder were designed in our laboratory. Hence it was found that the primary alkyl radical (1),-CH_2CH CH_2-was produced by the HVB at 77K. And this radical was found to convert into a polyenyl radical(II),-CH_2-CH CH=CH_n by the heat treatment of the sample. The line width of the observed radical,II showed a typical motional narrowing, like that of polyacetylene synthesized by Zieglar catalyst. Therefore the polyenyl radical which showed a singlet ESR signal can be called soliton as well as -radical stabilized in the main-chain of the ordinary polyacetyleneThe double bond produced by the breakdown was found to increase when the reaction was carried out at room temperature. And also it was found that the conductivity of the polyacetylene created in the PE showed an increase of 6-7 magnitudes by doping with iodine as electron acceptor.