Single-Electron Transfer Living Radical Polymerization (SET−LRP) of Methyl Methacrylate (MMA) with a Typical RAFT Agent as an Initiator

Abstract

A typical reversible addition−fragmentation chain transfer (RAFT) agent, 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN), was used as a single electron transfer-living radical polymerization (SET−LRP) initiator for methyl methacrylate (MMA) polymerization at 25 °C. At 1:1 molar ratio of [CPDN]0/[Cu(0)]0, the apparent rate constants of propagation (kpapp) were 0.037, 0.049, and 0.072 h−1 for [MMA]0/[CPDN]0 of 225/0.2, 225/0.5, and 225/1, respectively. The number-average molecular weight of poly(methyl methacrylate) (PMMA) increased linearly with monomer conversion, and narrow molecular weight distributions (Mw/Mn < 1.50) were found at most cases. At high molar ratio of [CPDN]0 to [Cu(0)]0, such as 1:0.1 in this work, the polymerization was also controllable, whereas it a presented markedly depressed polymerization rate and an obvious induction period. 1H NMR spectroscope and matrix assisted laser desorption/ionization time-of-flight mass spectrometry confirmed that PMMA chain was end-capped by CPDN species wit...