Since tertiary amines (Cα-H) can be oxidized by peroxides and transition metal cations in high oxidation states into Cα· radicals to initiate vinylic polymerizations of methacrylates, Cu2+ and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) form a polymerizable redox initiating pair, in which DMAEMA serves as an intrinsically reducing inimer. CuSO4 -catalyzed aqueous self-initiated radical polymerizations of DMAEMA were successfully performed at ambient temperature via a continuous Cu2+-tertiary amine redox initiation based on catalyst regeneration in the presence of O2 . The polymerization kinetics was monitored by gas chromatography and the structure of PDMAEMA was characterized by gelpermeation chromatography, nuclear magnetic resonance spectroscopy, laser light scattering and online intrinsic-viscosity analysis. Both the monomer conversion and the molecular weight of PDMAEMA increase with the reaction while the molecular weight distribution maintains rather broad, as the Cu2+-DMAEMA redox-initiation leads to linear PDMAEMA chains with terminal methacryloxyl moieties, and the Cu2+-PDMAEMA redox-initiation results in branched chains. The branched topology forms and develops only for the high-MW components of the PDMAEMA. Our results provide a facile strategy to prepare branched polymers from such commercially available intrinsically reducing inimers using a negligible concentration of regenerative air-stable catalysts.
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