SET-LRP of Acrylates in Air

Single Electron Transfer-Living Radical Polymerization (SET-LRP) represents a robust and versatile method for the rapid synthesis of macromolecules with well defined topology. In SET-LRP, certain combinations of solvents and ligands facilitate the disproportionation of in situ generated Cu(I) species into "nascent" Cu(0) and Cu(II) species. A combination of heterogeneous and "nascent" Cu(0) activation yields polymers with very high chain end functionality. Under suitable conditions the tolerance toward oxygen must be increased since Cu(0), the activator in SET-LRP, acts as an oxygen scavenger in all inert gas purification systems. Here we demonstrate that SET-LRP of methyl acrylate can be conducted in the presence of air. The addition of a small amount of reducing agent hydrazine hydrate to the reaction mixture reduces Cu2O generated by the oxidation of Cu(0) with air, regenerating Cu(0) and allowing for the synthesis of polymers with predictable molecular weight and perfect retention of chain end functionality. The kinetics plots obtained under these conditions were identical to these generated by degassed samples. High conversions were achieved within a very short reaction time. In these SET-LRP experiments, the reagents were not deoxygenated or subjected to standard degassing procedures such as freeze-pump-thaw or nitrogen sparging. This simple SET-LRP procedure provides an efficient and economical approach to the synthesis of functional macromolecules. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1190-1196, 2010