| abstract |
PURPOSE: To obtain the titled polymer having an arbitrary MW in a specified range, by polycondensing an organotrihydroxysilane to the desired MW by heating under a pressure in the presence of a catalyst and stopping the polycondensation by adding a silylating agent to the reaction system. n CONSTITUTION: An organotrihydroxysiland obtained by the hydrolysis of an organotrichlorosilane is polycondensed by heating under a pressure of N 2 in the presence of an organic amine (e.g., triethylamine) as a catalyst. The weight- average MW increases with the lapse of time. When this MW reaches the desired value, the polycondensation is stopped by adding a silylating agent such as an organomonohalogenosilane or an organomonoisocyanatosilane to the reaction system to obtain a silylated polyorganosilsesquioxane (polymer) of the formula (wherein n is 50W5,000 and R is CH 3 , C 2 H 5 or phenyl) having any desired weight-average MW within the range of from 10 4 to 10 5 . n COPYRIGHT: (C)1986,JPO&Japio |