空间质子与电子综合辐照作用下甲基硅橡胶破坏模型

A Model for Destruction of the Methyl Silicone Rubber Net-structure after the Synergistic Radiation of Proton and Electrons

利用空间辐照环境模拟设备对甲基硅橡胶进行了质子、电子综合辐照试验 .质子、电子的辐照能量均为 15 0keV ,辐照剂量均为 10 16cm-2 .质谱测试发现 ,综合辐照过程中有CH3 Si(O)CH3 气体生成 .量子化学计算表明 ,H+ 直接进攻硅橡胶高分子链中的氧而导致高分子链断裂的过程要放热 65 5 3 4kJ/mol,是唯一的放热反应通道 .这一过程不会形成稳定的过渡态和中间体 ,而是直接形成断键产物 .计算分析结果与综合辐照形成的气体产物CH3 Si(O)CH3 相吻合 .

Synergistic radiation effect on methyl silicone rubber of protons and electrons was investigated using a ground-based simulator for space radiation environment. The energy of protons and electrons was chosen as 150 keV, and the fluence 10(16) cm(-2). The gas product is CH3Si(O)CH3 by mass spectrum after synthesized radiation. The quantum chemistry calculation indicated that the macro-molecule chains in the silicone rubbers could be fractured by a direct attack of H+ to the oxygen in the chains. This process was an only exothermic channel, giving out the heat of 655.34 kJ/mol. No stable transition states and intermediate products were formed, except for the fractured pieces of the chains. The calculation result was in agreement with the gas product CH3Si(O)CH3 formed by synergistic radiation of proton and electrons.