In the (Very) Long Run We Are All Dead: Activation and Termination in SET-LRP/SARA-ATRP

The rate constants of activation and termination were determined for SET-LRP/SARA-ATRP polymerizations of methyl acrylate. Measurement of the rate of generation of CuBr₂ throughout the reaction (using data from Levere et al., Macromolecules 2012, 45, 8267-8274) allowed evaluation of the chain length dependence of the two rate constants, which were found to be 1.25(9) × 10^-4DP_n^-0.51(3) cm·s^-1 (activation) and 3.1(1) × 10⁹DP_n^-0.49(2) L·mol^-1·s^-1 (termination). Addition of the CuBr₂ deactivator at the beginning of the reaction is found to result in a higher proportion of dead chains due to rapid termination of short chains.