多官能度大分子交联剂对硅橡胶耐热性能的影响

Improvement of Thermal Resistance of Polydimethylsiloxanes with Multifunctional Crosslinker

以多官能度的聚甲基甲氧基硅氧烷(PMOS)作为大分子交联剂,与端羟基聚硅氧烷橡胶通过室温水解缩合反应而固化。多官能度的PMOS在硅橡胶中原位生成了大量高密度多官能度的PMOS相,使硅橡胶的交联密度增大。热重法(TG)测试表明,多官能度的PMOS交联硅橡胶500℃的质量残留率为66%,计算得出热降解反应级数为0.974、热降解反应表现活化能为78.0 kJ/mol。X射线光电子能谱分析(XPS)表明多官能度的PMOS相阻碍了硅橡胶的热降解反应,提高了硅橡胶的耐热性能。

Polymethylmethoxysiloxane （PMOS） was employed as the crosslinking agent of polydimethylsiloxane （PDMS）. High-erosslinked PMOS phases were in-situ formed and the average crosslink density increased as the loading of PMOS went up. The residual mass at 500 ℃ was 66 %, the pyrolysis reaction order was 0. 974 and the activation energy for degradation was 78.0 kJ/mol. It was detected that dense PMOS phases can reduce the pyrolysis of polydimethylsiloxane at elevated temperature.