Highly efficient and well-controlled ambient temperature RAFT polymerization of glycidyl methacrylate under visible light radiation

A range of well-defined poly(glycidyl methacrylate) (PGMA) polymers and their corresponding block copolymers were synthesized via 2-cyanoprop-2-yl(4-fluoro) dithiobenzoate or CPFDB-mediated ambient temperature reversible addition fragmentation chain transfer radical polymerization or RAFT polymerization under environmentally friendly visible light radiation (λ = 405-577 nm), using a (2,4,6-trimethylbenzoyl) diphenylphosphine oxide photoinitiator. As comparison, CPFDB-mediated ambient temperature RAFT polymerizations of glycidyl methacrylate (GMA) under both full-wave radiation (λ = 254-577 nm) and long-wave radiation (λ = 365-577 nm) were also studied in this article. The results indicated that CPFDB moieties were significantly photolyzed under either full-wave radiation or long-wave radiation, thus undermining the controlled behavior of these RAFT processes. Whereas this photolysis was significantly suppressed under visible light radiation, thus CPFDB functionalities exerted well control over RAFT process, leading to a remarkably living behavior up to 90% GMA monomer conversions. This strategy facilitates the facile synthesis of well-defined PGMA polymers. More importantly, under visible light radiation, a relatively high initial molar ratio of GMA to CPFDB and TPO led to shortening initialization period of RAFT process and accelerating overall polymerization rate. These effects are remarkably in favor of the facile synthesis of well-defined PGMA polymers and PGMA-based copolymers with high molecular weights. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5091-5102, 2007