| abstract |
Siloxane-carbonate block copolymers are prepared by reacting (A) at least one siloxane compound with (B) at least one polycarbonate compound, one of reagents A and B being anionic and the other being reactive with nucleophiles. The siloxane compound is preferably a linear chlorosilane-terminated polysiloxane, a cyclic polysiloxane or a "living" polysiloxane anion. The polycarbonate composition may be a cyclic polycarbonate oligomer composition, preferably an oligomer mixture, or may be prepared by the reaction of such an oligomer composition with a polycarbonate formation catalyst such as tetramethylammonium tetraphenylborate. |