- Rate optimization in controlled radical emulsion polymerization using RAFT. SW Prescott, MJ Ballard, E Rizzardo and RG Gilbert. Macromolecular Theory and Simulations, 15, 70–86, 2006.
Means of improving rates in RAFT-mediated radical emulsion polymerizations are developed, by setting out strategies to minimize the inhibition and retardation that always are present in these systems. These effects arise from the RAFT-induced exit of radicals, the desorption of the RAFT-reinitiating radical from the particles, and the specificity of the reinitiating radical to the RAFT agent. Methods for reducing the inhibition period such as using a more hydrophobic reinitiating radical are predicted to show a significant improvement in the inhibition periods. The time-dependent behavior of the RAFT adduct to the entering radical and the RAFT-induced exit (loss) of radicals from particles are studied using a previously described Monte Carlo model of RAFT/emulsion particles. It is shown that an effective way of reducing the rate coefficient for the exit of radicals from the particles is to use a less active RAFT agent. Techniques for improving the rate of polymerization of RAFT/emulsion systems are suggested based upon the coherent understanding contained in these models: the use of an oligomeric adduct to the RAFT agent, a less water-soluble RAFT re-initiating group, and a less active RAFT agent.
Last edited: Friday September 10, 2010
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