Single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization of vinyl chloride catalyzed by thiourea dioxide/octyl viologen in water/tetrahydrofuran at 25 °C

The single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization (SET-DTLRP) of vinyl chloride (VC) in H2O/tetrahydrofuran at 25 degreesC catalyzed by thiourea dioxide [(NH2)(2)C=SO2] is reported. This polymerization occurs only in the presence of a basic sodium bicarbonate (NaHCO3) buffer and the electron-transfer cocatalyst octyl viologen. The resulting poly(vinyl chloride) (PVC) has a number-average molecular weight of 1500-7000 and a weight-average molecular weight/number-average molecular weight ratio of 1.5. This PVC does not contain detectable amounts of structural defects and has both active chloroiodomethyl and inactive chloromethyl chain ends. Because of possible side reactions caused by the primary sulfoxylate anion (SO22-), the catalytic activity of (NH2)(2)C=SO2 in the SET-DTLRP of VC is lower than that of the single-electron-transfer agent sodium dithionite. (C) 2004 Wiley Periodicals, Inc.