A highly efficient oxygen tolerant visible-light mediated RAFT polymerization

Abstract

Recently, oxygen-tolerant reversible addition-fragmentation chain transfer (RAFT) polymerization has attracted increasing attention in polymer chemistry. Inspired by the monomers containing glycol ethers group have high polymerization rates and even achieved a desirable oxygen tolerance. Herein, we proposed a simple, effective, low-cost, and eco-friendly strategy to accomplish the oxygen-tolerant visible-light activated RAFT polymerization of acrylates and acrylamides in a mixed solution of glycol ether and water at ambient temperature. This photo-mediated RAFT polymerization does not require additives, prior deoxygenation, or inert gas protection. The acrylates and acrylamides with high conversion under irradiation for 2 h, and the resulting polymers were narrow unimodal and narrow molecular weight distributions (PDI<1.3). In addition, the “living” and well-controlled behaviors of this oxygen-tolerant photo-mediated RAFT polymerization were demonstrated through water content in solvents, headspace, initial concentration of monomers, various monomers, chain lengths, light ON/OFF experiment, and high-end group fidelity of block copolymers. This RAFT polymerization also opens up a wide avenue for the industrial production of functional polymeric materials via an in situ chain extension strategy. These results indicate that the mixed solution of glycol ethers and water are effective green media for promoting photo-mediated RAFT polymerization without additives or tedious degassing processes.