STUDY ON GRAFTING POLYMERIZATION OF METHYL-METHACRYLATE ON THE SURFACE OF SILICONE-RUBBER PARTICLES INITIATED BY GAMMA-RAY OF CO-60 DURING THE SEEDED EMULSION POLYMERIZATION

A stable seeded emulsion system containing silicone rubber particles w as prepared by using homogenizer. Grafting efficiency far below 100% i mplies the generation of new poly(methyl methacrylate) [PMMA] particle s. The maximum value on the curve of homopolymerized MMA/the added MMA against irradiation dose was observed. After the monomers in the syst em were almost consumed, grafting ratios increased. The addition of so dium bromide into water phase increase the grafting efficiency. The ef fect of types of emulsifiers used in the emulsion system on grafting r atios indicates the differences of monomer partition between the seede d particles and water. When OP-10 was used as emulsifier, one hundred percent of grafting efficiency was obtained. The pictures taken by Hit achi H-80 TEM of the seeded particles, particles grafted with MMA and the seed grafted with styrene show the formation of new PMMA particles , and the compatibility difference of two monomers with silicone rubbe r. To explain the experimental results, a reaction mechanism for the s eeded emulsion polymerization is proposed.