硅橡胶中的正电子湮没寿命谱实验分析

A NALYSIS OF POSITRON ANNIHILATION

本文用硅橡胶材料做正电子湮没的实验,实验的结果得到了硅橡胶中正电子湮没三种成份的寿命均随分子量增大而减小,以及生胶在高温硫化前后的正电子湮没三种成份寿命和相应的强度有显著变化。根据硅橡胶大分子的结构来分析影响正电子湮没三种成份寿命的因素,随着分子量的增大,大分子链变长,单位体积中链的自由末端减小,使得硅橡胶的密度增大,乙烯基的密度增大,正电子湮没第一寿命减小;单位体积大分子链间的缠绕和交叠也随分子量增大而增多,使正电子湮没第二寿命减小;大分子间的额外空隙随着聚合物的密度增大而减小,使正电子湮没第三寿命减小。用这个观点对实验结果作了解释。

This article presents an experiment of postron annihilation in polyvinylmethy siloxane. It is shown that three lifetime componets of postron annihilation were reduced with the increase of molecular weight, and that lifetime and intensities are obviously different before and after sulphonation at a high temperature. The factors which affect postron annihilation lifetime were analysed on the basis of the constitution of polyvinyylsi-loxane. It is shown that the density of polyethylene radicals, the chain-kinks, and folds in the molecule increase while the free volum decreased with molecular weight.