Ligand‐free SET‐DTLRP of MMA at room temperature

An iodine‐based initiator, 2‐iodo‐2‐methylpropionitrile (CPI), was utilized for the single‐electron transfer and degenerative chain transfer mediated living radical polymerization (SET‐DTLRP) of methyl methacrylate (MMA) in the absence of ligand, at ambient temperature. The CPI‐initiated ligand‐free polymerizations manifested reasonable control over molecular weights with relatively narrow distributions (M_w/M_n ≤ 1.35). The living nature of the polymers was further confirmed by successful chain extension reaction and ¹H NMR with high chain‐end fidelity (～96%). Screening of the available solvents suggested that the controllability of this polymerization was highly dependent on the kind of solvents, wherein dimethyl sulfoxide was a better solvent for a controlled molecular weight. The proposed ligand‐free SET‐DTLRP initiated by CPI was intriguing since it would dramatically decrease the concentration of Cu(0) ions both in polymerization system and resultant polymer, and provided a more economical and eco‐friendly reversible‐deactivation radical polymerization technique. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013