六甲基环三硅氧烷非平衡聚合的研究

六甲基环三硅氧烷(D_3)在为催化剂,二甲亚砜为促进剂的情况下聚合,得到了分子量分布窄且没有大环体的聚二甲基硅氧烷。本文指出了反应溶液中溶解的氧会降低催化剂的活性。在除去了溶液中的氧以后,聚合反应速度大为加快,D_3转化率几乎达100％,而且得到的聚合物是活性高分子,可以继续进行聚合。同时还研究了在除氧以后D_3非平衡聚合反应的特点。

STUDIES ON THE NONEQUILIBRIUM POLYMERIZATION OF HEXAMETHYL CYCLOTRISILOXANE

The polydimethylsiloxane with a very narrow molecular weight distribution and free of macrocyclics was synthesized by polymerization of hexamethylcyclotrisloxane (D,) in toluene with benzyltrimethylammonium bis (o-phenylenedioxy) phenylsiliconate as a catalyst and dimethyl sulfoxide (DMSO) as a promoter. Oxygen must be excluded, otherwise it would lower the reactivity of the catalyst. As oxygen is removed from the reaction system, the rate of the polymerization is obviously increased and D, can be converted to polymer approximately to 100 percent. The polydimethylsiloxane thus obtained is a living polymer. Characteristics of the nonequilibrium polymerization of D, in the absence of oxygen were investigated.