Tailored polymers by free radical processes

This paper describes a versatile and effective method for the control of fr ee radical polymerization and its use in the preparation of narrow polydisp ersity polymers of various architectures. Living character is conferred to conventional free radical polymerization by the addition of thiocarbonylthi o compound of general structure S = C(Z)SR, for example, S = C(Ph)SC(CH3)(2 )Ph. The mechanism involves Reversible Addition-Fragmentation chain Transfe r and, for convenience of referral, we have designated it the RAFT polymeri zation. The process is compatible with a very wide range of monomers includ ing functional monomers such as acrylic acid, hydroxyethyl methacrylate, an d dimethylaminoethyl methacrylate. Examples of narrow polydispersity (less than or equal to 1.2) homopolymers, copolymers, gradient copolymers, end-fu nctional polymers, star polymers, A-B diblock and A-B-A triblock copolymers are presented.