Combined catalytic reactions : an integrated biocatalytic approach in polymer chemistry

A new concept for the synthesis of block copolymers combining enzymic ring opening polymn. and controlled free radical polymn. employing bifunctional initiators is described. The combination with atom transfer radical polyerization (ATRP) results in well defined polymers in a two step approach whereas competing reactions kinetics limits the feasibility of a one pot approach. This can be circumvented by nitroxide mediated controlled free radical polymn. Block copolymers were obtained by a one-pot cascade approach without an intermediate transformation or work up step. Preliminary results imply that the temp. induced kinetic sepn. favors the block polymer formation by circumventing the sterically disfavorable polystyrene macroinitiation. [on SciFinder (R)]