聚甲基倍半硅氧烷的合成

Synthesis of polymethylsesquisiloxane

以甲基三氯硅烷 (CH3SiCl3)为主要原料、乙二胺为梯形控制剂 ,合成了聚甲基倍半硅氧烷 ,讨论了梯形控制剂、水解介质、催化剂、单体浓度、温度等因素对聚合物摩尔质量及结构规整性的影响 ,筛选出较佳的梯形控制剂和聚合条件。结果表明 :nCH3SiCl3∶n乙二胺 为 1∶1 1,产物收率接近 90 % ,水解时nCH3SiCl3∶nH2 O为 1∶15产物摩尔质量大 ,且规整性好 ;水解后 ,若以四甲基氢氧化铵为催化剂、缩合反应温度为 3 5℃时 ,若反应时间长 ,聚合物摩尔质量高、分布宽 ;反应时间短 ,则聚合物摩尔质量低、分布窄。若以酸作催化剂、缩合反应温度为 80℃时 ,聚合物摩尔质量较低。

Methylsesquisiloxane was synthesized by taking methyltrichlorosilane as raw material and organic amine as trapezium control agent. The effects of trapezium control agent,hydrolyze medium,catalyst,monomer consistency,temperature on molar mass and structure regularity of polymer were discussed. Agreeable trapezium control agent and polymerization condition were filtered out. When the molar ratio of methyltrichlorosilane and ethylenediamine equals to 1∶1 1,product yield was higher,about 90%. When the molar ratio of methyltrichlorosilane and H 2O equals to 1∶15,product had a larger molar mass and good regularity. After the hydrolization,when taking tetramethyl ammonium hydroxide as catalyst,condensation reaction was carried out at 35 ℃,if reaction time was short,the product had low molar mass and narrow distribution of molar mass. On the other hand,if reaction time was long,the product had high molar mass and wide distribution of molar mass. When taking acid as catalyst the condensation reaction was carried out at higher temperature,by lower molar mass of polymer and narrow distribution of molar mass.