PREPARATION OF POLYMER PARTICLES IN AEROSOL-PHASE REACTION

Polymer (polysiloxane, polystyrene) particles were prepared by polymer izing droplets of monomer (methyltrichlorosilane, styrene) with vapor (water, trifluoromethanesulfonic acid) in aerosol reactor. The droplet s were produced by either evaporation-condensation or nebulization. Th e applicability of the droplet production methods depends on the natur e of the polymerization systems. In the step polymerization of polysil oxane, the evaporation-condensation route gave better results while, i n the chain polymerization of polystyrene, the nebulization method was preferred to the other. The evaporation-condensation method was limit ed in its ability to produce appreciable amounts of polymer product du e to its dependence on monomer vapor pressure. In the nebulization tec hnique for the preparation of polystyrene particles, the addition of v arious volatile additives to the styrene monomer to be nebulized made it possible to change the average size, size distribution and surface characteristics of the particles. Also, the combination of the aerosol techniques made it possible to prepare composite particles of polysil oxane-coated polystyrene with a core-shell structure.