It was demonstrated that the fast RAFT polymerization of styrene with almost perfect polymerization performance could be achieved by using a carefully designed miniemulsion polymerization system.With much higher levels of surfactant (9 wt% based on monomer) and co-stabilizer (5 wt% based on monomer) than those in typical miniemulsion polymerization,the miniemulsion polymerization using 1-phenylethyl phenyl-dithioacetate as a RAFT agent showed a very fast polymerization rate,excellent performance of living radical polymerization during the entire polymerization process,and narrow particle size distributions.It was concluded that RAFT miniemulsion polymerization presented an excellent commercial process for a living radical polymerization system.
Monte Carlo simulation technique was used to simulate the scenarios of the very beginning of a particle in RAFT seeded emulsion polymerization. It was first found that by introducing a high reactive RAFT agent, a large number of free radical need to be captured by the particle before polymerization starts up. The phenomenon was ascribed to the high reactivity of RAFT agent and fast exit of fragmented group of the original RAFT agent. The simulations could be successfully used to explain an unexpected long induction period and polymerization retardation reported. The results of this study will be of particular use in understanding and design of RAFT emulsion polymerization.
