Polymerizations of methyl methacrylate in microemulsion stabilized with emulsifier BOA were initiated with γ ray

KPS

BPO and AIBN

respectively.The microemulsion with high monomer content remained clear after polymerization.The growth of particles and their size distribution were detected at different conversions.The average hydrodynamic diameter of final polymer particles was between 50～70nm.It was found that there was some resemblance among polymerization initiated with the four initiators.However

there were also obvious differences.When the microemulsion polymerization was initiated with KPS or γray

homogenous nucleation predominated at low conversion

and micellar nucleation dominated at high conversion.When it was initiated with BPO or AIBN

at low conversion

polymerization mainly took place in the big droplets

and micellar nucleation became the only nucleation route at high conversion.