BLOCK-COPOLYMER PREPARATION USING SEQUENTIAL NORMAL LIVING RADICAL POLYMERIZATION TECHNIQUES/

Anionic and nitroxide-mediated (NM) radical polymerization works well for styrene but not for acrylates. We have overcome this problem and s uccessfully prepared styrene-b-n-butyl acrylate (S-BA), styrene-b-meth yl methacrylate (S-MMA), styrene-b-isoprene (S-IP), and styrene-alt-ac rylonitrile-b-isoprene (SAN-IP) polymers using a sequential normal/liv ing radical polymerization scheme. Clear (S-IP and SAN-IF) to transluc ent (S-BA and S-MMA) films were obtained having microphase-separated p olymer morphology. GPC studies and chemical digestion of the IP segmen ts of S-IP and SAN-IF block copolymers confirmed their block structure . The sequential normal/living radical polymerization approach provide s a new route to synthesize block polymers that have previously proven very difficult to make.