Synthesis of Micrometer-Size Poly(Methyl Methacrylate) Particles by Utilizing Microsuspension Iodine Transfer Polymerization (ms ITP): Kinetic Approach

In a previous work, microsuspension ITP (ms ITP) of methyl methacrylate (MMA) using iodoform (CHI₃) as a chain transfer agent and benzoyl peroxide (BPO) as an initiator could be successfully carried out at 80 °C for the synthesis of micrometer-size poly(MMA) (PMMA) particles without the byproduct of submicrometer-size particles. Whereas, in microsuspension conventional radical polymerization (ms CRP) at the same conditions except for non-use of CHI₃, about half amount of PMMA was formed as submicrometer-size byproduct particles by accompanying emulsion polymerization. In this article, kinetic simulations of ITP and CRP in bulk systems, which, respectively, correspond to those within MMA droplets in ms ITP and ms CRP, are performed using PREDICI software from CiTGmbH to understand the successful reason of the ms ITP of MMA. The simulation results of the ITP indicate that the concentrations of MMA oligomer radicals having BPO initiator fragment and vinyl group as end-group, which seem to exit from MMA droplets and accompany emulsion polymerization in the aqueous medium in the ms CRP, remarkably decreased in the presence of CHI₃. This strongly supports the idea “RED effect” proposed in the previous article to explain the success of the ms ITP of MMA.