【摘要】 当引入0.1—1.5％聚铝苯基硅氧烷作为聚甲基苯基硅树脂固化催化剂时,后者由甲阶向乙阶转变时的聚合速度显著地增加;聚合反应表观活化能约由无催化剂存在时的26千卡/克分子降为20千卡克分子,改变催化剂的含量对表观活化能影响很小。表观频率因子随催化剂用量增加而增加,催化剂用量为0.6％时约增加一个数量级。 热固化的聚甲基苯基硅树脂的侧基显示出不同的热氧化稳定性。在空气中增高温度时其侧基破坏分为二个阶段,即甲基比苯基先破坏。当引入聚铝苯基硅氧烷作为硅树脂 固化催化剂,可提高其甲基的起始分解温度,同时降低苯基的起始分解温度。随催化剂用量的增加,使二种侧基起始分解温度趋于一致,逐渐消失其侧基破坏的阶段性。更多还原

【Abstract】 With 0.1-1.5% polyaluminophenylsiloxane as catalyst, the rate of curing of poly-methylphenylsiloxane resin increases. The apparent energy of activation of curing falls from 26 kcal/mole in the absence of the catalyst to 20 kcal/mole in its presence, being little affected by the amount of catalyst used. However, the apparent frequency factor of curing increases with the increase of the catalyst, being one order of magnitude higher with 0.6 % catalyst than without.There are two stages in the thermal oxidative degradation of the thermally cured polymethylphenylsiloxane resin. The methyl groups decompose at a much lower temperature than the phenyl groups. The addition of the polyaluminophenylsiloxane during the curing of the resin raises the initial temperature of decomposition of the methyl group and lowers that of the phenyl group. With increasing amount of the catalyst used, the difference in the temperature of decomposition gradually diminishes.更多还原