Eung-Chan Lee, Y. Kimura
Aug 1, 1997
Citations
0
Influential Citations
29
Citations
Journal
Polymer Journal
Abstract
Trichlorophenylsilane (TCP) was hydrolyzed in an toluene/water heterogeneous solvent system, and a low molecular weight hydrolysate with simple structure was isolated from the aqueous solution while a high molecular weight hydrolysate with complicated structure was isolated from the toluene layer. When this hydrolysis was conducted strictly at 0°C, the primary hydrolysate consisting mainly of phenylsilanetriol (PST) could be crystallized out from the aqueous layer. When the low molecular weight hydrolysate obtained from the aqueous layer was subjected to the KOH-catalyzed polycondensation in refluxing toluene, poly(phenylsilsesquioxane) (PPQS) with a highly ordered ladder structure could be obtained. Its molecular weight increased with decreasing molecular weight of the initial hydrolysate, and its silanol content oppositely decreased with it. Since this polycondensation proceeded stepwise, it has been considered that intramolecular cyclization is favored in the first condensation of the low molecular weight hydrolysate and that the resultant higher oligomers are then connected into high polymer with ladder structure by the silanol coupling. The molecular weight of PPQS finally obtained reached 120 kDa.