Thermolysis of RAFT-Synthesized Polymers. A Convenient Method for Trithiocarbonate Group Elimination

Abstract

Radical polymerization with thiocarbonylthio RAFT (reversible addition-fragmentation chain transfer) agents 1-4 is arguably one of the most versatile processes for living free radical polymerization displaying superior flexibility with respect to monomers and reaction conditions. A key feature of RAFT polymerization is that the thiocarbonylthio group(s), present in the initial RAFT agent, is (are) retained in the polymeric product(s). The retention of these groups is responsible for the polymers’ living character. However, the presence of the thiocarbonylthio groups also means that the polymers are usually colored. The polymers may also, in some cases, be odorous or release an odor over time due to decomposition of the thiocarbonylthio groups and the evolution of volatile sulfur-containing compounds. The presence of such color and odor can be disadvantageous in some applications. Even though some of these issues may be largely mitigated or overcome by more appropriate selection of the initial RAFT agent, there has nonetheless been some incentive to develop effective methods for treatment of RAFT-made polymers to cleave the thiocarbonylthio end-groups postpolymerization.