Method for producing a polydiorganosiloxane having a pendent alkenyl radical at its molecular center.

摘要

Polydiorganosiloxanes which have a pendant alkenyl radical in the middle of the molecular chain are prepared by a nonequilibrium, living polymerization of cyclic trisiloxanes using an organopolysiloxane alkali metal salt of the formula <CHEM> where M is lithium, sodium, or potassium, which takes place under substantially anhydrous conditions, and the polymerization is terminated with an end-capping reaction to produce a polydiorganosiloxane of the formula <CHEM> where R<1> is an alkenyl radical. These polymers can be used to make graft copolymers and can be made more functional when the ends are capped with functional groups.