Evidence of compartmentalization in catalytic chain transfer mediated emulsion polymerization of methyl methacrylate

Evidence of compartmentalization of the catalytic chain transfer agent in seeded emulsion polymerization of methyl methacrylate (MMA) is shown experimentally. The addition of bis[(difluoroboryl)dimethylglyoximato]cobalt(II) (COBF) to seed particles swollen below their maximum saturation concentration exhibited multimodal molecular weight distributions (MWD) which are attributed to a statistical distribution of COBF molecules over the polymer particles. The experimental observations suggest that there are two limits for catalytic chain transfer in emulsion polymerization: (i) at the earlier stages of the polymerization where a global COBF concentration governs the MWD and (ii) at the latter stages of the polymerization where a statistical distribution of COBF molecules governs the MWD. To the best of our knowledge, these results are the first to suggest evidence of compartmentalization in catalytic chain transfer mediated emulsion polymerization