Reversible Addition Fragmentation Chain Transfer (RAFT) Polymerization with a Polymeric RAFT Agent Containing Multiple Trithiocarbonate Groups

Polytrithiocarbonates were prepared by the condensation polymerization of a dicarboxylic acid functional trithiocarbonate and a diol. These polymers were effective reversible addition fragmentation chain transfer (RAFT) agents for the bulk polymerization of polystyrene homopolymers and a poly [styrene-block-(tert-butylstyrene)] block copolymer. Size exclusion chromatography (SEC) analysis of the original and amine cleaved polymers showed that the polydispersity of the polymer tended toward two with increasing polymerization time, but the polydispersity of the polymer units between trithiocarbonate groups was narrow (ca. 1.1-1.3) Also, the average number of trithiocarbonate groups per chain was found to be proportional to the number of trithiocarbonate groups in the starting RAFT agent. These polytrithiocarbonate RAFT agents will be useful for preparing multiblock copolymers over a range of chemistries, block numbers and molecular weights.