B. Lessard, Christopher J. Tervo, M. Maríc
Jul 13, 2009
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0
Influential Citations
36
Citations
Journal
Macromolecular Reaction Engineering
Abstract
Tert-Butyl acrylate (TBA) was polymerized by nitroxide-mediated polymerization (NMP) using BlocBuilder initiator and 4.5 mol-% additional SG1 (N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide) relative to BlocBuilder (2-methyl-2-[N-tert-butyl-N-(diethoxylphosphoryl-2,2-(dimethylpropyl)aminooxy]propionic acid) at 115 °C in bulk and in various solvents. In all cases, number average molecular weight () increased linearly up to 35% conversion. kpK values (kp = propagation rate constant, K = equilibrium constant) for TBA agreed well with literature data. For higher target > 50 kg · mol−1, solution polymerizations used to reduce viscosity were problematic as chain transfer reactions became noticeable, particularly when block copolymers with styrene were desired. A better strategy to obtain high block copolymers involved a semi-batch feeding in bulk of styrene monomer to a poly(TBA) macroinitiator which resulted in high gradient blocks with low polydispersity ( = 54.7 kg · mol−1, = 1.3).