Preparation of Copolymers by Ring-Opening Polymerization

Similarly, copolymerizing a mixture of [Me2SiO]4 and [Si(Me)(CH=CH2)0]4 affords poly(dimethylsiloxane-co- 

Ring-opening polymerization of cyclosiloxanes can be carried out by either cationic or anionic initiators. 

Polymerization by cationic initiators occurs either by protic or Lewis acids. Different types of mechanisms of polymerization have been proposed such as acidolysis/condensation, oxonium ion-mediated polymerization or silylium ion-mediated polymerization. 

Anionic polymerization can be carried out by metal hydroxides or even by lithium salts of silanols. This method of polymerization affords high-molecular-weight polymers. 

The polymers have to be terminated by Me3Si groups to afford stable products. 

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