Linear and Star-Branched Siloxy-Silane Polymers: One Pot A-B Polymerization and End-Capping

: Silane and siloxane polymers form an important family of commercial materials. They pose a unique combination of thermal stability, hydrophobicity, and segmental mobility which gives them low temperature flexibility and properties useful in demanding application where their high cost is justified. Recent reports of silicone dendrimers make available single-molecule structures which greatly extend these potential uses. We have developed an alternative approach to siloxy-silane hyperbranched polymers that uses an A-B3 monomer possessing one alkene moiety and three Si-H groups. Addition of a platinum hydrosilation catalyst leads to rapid formation of polymer with a high relative content of terminal Si-H groups that can be reacted (end-capped) with a variety of alkenes such as allyl phenyl ether and the allyl ether-monomethyl ether of oligooxyethylene.