USE OF CYCLIC CARBONATE OLIGOMERS IN THE SYNTHESIS OF BISPHENOL-A POLYCARBONATE-POLYDIMETHYLSILOXANE COPOLYMERS

Polydimethylsiloxane-polycarbonate block copolymers were prepared by sequential anionic polymerizations of cyclic carbonate oligomers and octamethylcyclotetrasiloxane, or by reaction of hydroxy-terminated polydimethylsiloxane oligomers with cyclic carbonates or by reaction of hydroxy-terminated polycarbonate oligomers (derived from cyclic carbonates) with chlorine-terminated polydimethylsiloxane oligomers. The use of cyclic carbonates for making the copolymers afforded a synthetic flexibility not available through conventional methods involving phosgene.