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Procuction of Polyacetylene from Polyethylene Induced by High Voltage Breakdown

高压击穿聚乙烯制聚乙炔

基本信息

批准号：
61470097
负责人：
TABATA Masayoshi
金额：
$ 4.29万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

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.

结果表明，聚乙烯（PE）高压击穿（HVB）并形成伯烷基自由基可以产生新的聚乙炔。据我们所知，迄今为止，还没有详细报道和通过ESR方法表征PE作为绝缘体击穿产生的不稳定化学物质。因此，有必要了解PE粉末在击穿过程中会产生哪些不稳定的化学物质，并从基础科学和工业应用的角度来研究PE粉末击穿的机理。我们实验室设计了用于PE粉末击穿的专用样品管和电路。因此发现伯烷基(1)，-CH_2CH CH_2-是由HVB在77K下产生的。通过对样品的热处理，发现该自由基转化为多烯自由基(II)，-CH_2-CH CH=CH_n。观察到的自由基II的线宽表现出典型的运动变窄，类似于Zieglar催化剂合成的聚乙炔。因此，显示出单线态ESR信号的多烯基自由基可以称为孤子，并且稳定在普通聚乙炔主链中的β自由基。发现当反应在室温下进行时，由断裂产生的双键增加。并且还发现，通过掺杂碘作为电子受体，PE中产生的聚乙炔的电导率增加了6-7个数量级。