质子辐照空间级硅橡胶的正电子淹没寿命谱研究

 用正电子淹没寿命谱方法（PALS）研究了质子辐照对空间级硅橡胶KH-L-Y微观结构的影响。试验结果表明，PALS谱所揭示的最长寿命成分的t₃, I₃及自由体积分数Vf随辐照剂量的增加开始明显下降；而当辐照剂量大于10¹⁵cm^-2后，随剂量的增加平缓上升。辐照剂量小于10¹⁵cm^-2时，质子辐照使硅橡胶自由体积减小，分子链间堆砌紧密；辐照剂量大于10¹⁵cm^-2时，质子辐照使硅橡胶自由体积增大。交联密度及DMA测试结果同样表明，质子辐照在剂量较小时硅橡胶的交联密度及玻璃化转变温度增加，辐照以交联效应为主；而剂量较大时辐照降解占优势。

Study on positron annihilation lifetime spectrum of polysilicone rubber after proton radiation

The positron annihilation lifetime spectrum(PALS) method was employed to study the effect of proton radiation on microstructure of the space grade KH-L-Y polysilicone rubber. The results show that both τ 3 and I 3 of the longest lifetime component and the free volume V f decrease with the increase of the radiation fluence at the beginning and become level off after 10 15cm -2 radiation fluence. The proton radiation causes decrease in both the free volume of polysilicone rubber, and the distance between the molecules when the radiation fluence is less than 10 15cm -2. However, the proton radiation makes the free volume of silicon rubber increase when the radiation fluence is greater than 10 15cm -2. Both the experimental results of the cross-linking density and DMA indicate that the cross-linking effect due to the proton radiation is predominant in the range of small proton radiation fluence, while the radiation degradation become superior when the proton radiation fluence is larger.