Polycondensatioh of Alkoxysilanes in an Active Medium As a Versatile Method for the Preparation of Polyorganosiloxanes

摘要

Hydrolytic polycondensation of functional derivatives of silicon is an important method for preparation of polysiloxanes of different structure ranging from organocyclosiloxanes to high-molecular-weight linear, cyclolinear, or branched polymers. The most widely used version of hydrolytic polycondensation is based on the use of organochlorosilanes. More than a five decade history of the industrial use of this process resulted in a broad range of organosilicon compounds without which modern technology cannot even be imagined. However, until now, it was impossible to solve two fundamental problems, namely, eliminate the use of chlorosilanes in polysiloxane preparation processes and carry out hydrolytic polycondensation under homogeneous conditions. The significance of the first issue is obvious in view of the need to decrease the environmental pressure. Currently, the use of alkoxy derivatives instead of organochlorosilanes is held up not only by the lack of industrial direct synthesis of organoalkoxysilanes but also by the difficulty to control the polymer production processes from these raw materials. The solution of the latter problem would markedly increase the process controllability, most of all, through control of the product structures.