摘要
用恒温热失重方法，研究了甲基硅橡胶（Ｓｉ—Ｏ—１），用氢氧化钾催化聚合的甲基硅橡胶（Ｓｉ—Ｏ—２），主链含环二硅氮烷的硅氮橡胶（Ｓｉ—Ｎ—１）以及它与Ｓｉ—Ｏ—１的共混物Ｓｉ—Ｏ—３和与Ｓｉ—Ｏ—２的共混物Ｓｉ—Ｏ—４的热降解反应动力学．结果表明Ｓｉ—Ｎ—１有最高的热稳定性，在氮气下，其降解反应活化能为３４４ｋＪ／ｍｏｌ．并且发现它分别与Ｓｉ—Ｏ—１和Ｓｉ—Ｏ—２的共混物的热稳定性大幅度提高．Ｓｉ—Ｏ—３在氮气下的降解活化能由未加入Ｓｉ—Ｎ—１前的１５２ｋＪ／ｍｏｌ提高到２３０ｋＪ／ｍｏｌ；Ｓｉ─Ｏ─４则由未混入Ｓｉ─Ｎ─１前的６１ｋＪ／ｍｏｌ提高到１４４ｋＪ／ｍｏｌ．我们认为这种作用机理是由于硅氮橡胶除去了微量吸附水和硅羟基并导致催化剂的离子对难于分离的结果．
he kinetics of thermal degradation for polydimethylsiloxane(Si-O- 1),polydimethylsiloxane containing residual basic catalyst(Si-O-2), silicone gums containing cyclodisilaZane (St-N-1), Si-O-3 by incorporation of Si-N-1 into Si-O-1 and Si-O-4 by incorporation of Si-N-1 into St-O-2 were studied by the isothermal gravimetric analyses (IGA) in nitrogen atmosphere. The results indicated that Si-N-1 has outstanding thermal stability. The activation energy of degradation is 344kJ /mol. Si-O-1 undergoes the thermal degradation with the activation energy of 152kJ /mol, while the activation energy of degradation energy for Si-O-3 is 230 kJ / mol in presence of Si-N -1. The activation energy of degradationfor Si-O-4 is 144kJ / mol, while Si-O -2 has only 62 kJ / mol in absence of Si-N -1.The enhancement of thermal stability for Si-O-4 is attributed to decreasing the loose ability of the catalyst ion pair when Si-N-1 removes the SiOH groups and water in the Si-O -4.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
1996年第2期202-209,共8页
Acta Polymerica Sinica
基金
国家自然科学基金
关键词
热稳定性
热降解动力学
硅橡胶
硅氮橡胶
Silicone rubber, Thermal stability, Kinetics of thermal degradation,Residual basic catalyst, Cyclodisilazane
