【摘要】 对掺杂了 2 5份 (phr)导电炭黑 (CB)的样品进行了正电子湮灭寿命谱的变温测量 ,在玻璃化转变温度以上 ,随着温度的增加 ,自由体积的大小线性增加 ,在玻璃化转变温度以下 ,自由体积的大小基本不变。o Ps的强度在 -4 0℃下基本不变 ,从-4 0℃以上开始增加 ,但在 5 0℃以上上升有加快的趋势。与PTC材料的PTC现象和导电性能有一定的关联更多还原

【Abstract】 The size and numerical concentration of free volume of HDPE/CB composites were estimated by means of positron annihilation lifetime measurement, in which annihilations of positron and positronium were assessed. From the variation of the ortho positronium (o Ps) lifetimes with the changes of temperature,we find that temperature dependence of positron lifetimes reveals that the existence of glass transition temperatures and size of free volume increases when temperature increases above glass transition . It was likely to test that PTC was probably closely related to hole size and therefore, conductivity may be deduced by the number of holes and the hole size.更多还原