SET-LRP of Methyl Acrylate Catalyzed with Activated Cu(0) Wire in Methanol in the Presence of Air

Single electron transfer-living radical polymerization (SET-LRP) of methyl acrylate (MA) in methanol, catalyzed with nonactivated and activated Cu(0) wires, was performed in the presence of nondeoxygenated reagents and was investigated under a simple blanket of nitrogen. The addition of a small amount of hydrazine hydrate mediates the deoxygenation of the reaction mixture by the consumption of oxygen through its use to oxidize Cu(0) to Cu2O, followed by the reduction of Cu2O with hydrazine back to the active Cu(0) catalyst. SET-LRP of MA in methanol in the presence of air requires a smaller dimension of Cu(0) wire, compared to the nonactivated Cu(0) wire counterpart. Activation of Cu(0) wire allowed the polymerization in air to proceed with no induction period, linear first-order kinetics, linear correlation between the molecular weight evolution with conversion, and narrow molecular weight distribution. The retention of chain-end functionality of alpha,omega-di(bromo) poly(methyl acrylate) (PMA) prepared by SET-LRP was demonstrated by a combination of experiments including H-1 NMR spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry after thioetherification of alpha,omega-di(bromo) PMA with thiophenol. In SET-LRP of MA in the presence of limited air, bimolecular termination is observed only above 85% conversion. However, for bifunctional initiators, the small amount of bimolecular termination observed at high conversion maintains a perfectly bifunctional polymer. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 4756-4765, 2011