Preparation of Polymer Particles in Aerosol-Phase Reaction

Polymer (polysiloxane, polystyrene) particles were prepared by polymerizing droplets of monomer (methyltrichlorosilane, styrene) with vapor (water, trifluoromethanesulfonic acid) in aerosol reactor. The droplets were produced by either evaporation-condensation or nebulization. The applicability of the droplet production methods depends on the nature of the polymerization systems. In the step polymerization of polysiloxane, the evaporation-condensation route gave better results while, in the chain polymerization of polystyrene, the nebulization method was preferred to the other. The evaporation-condensation method was limited in its ability to produce appreciable amounts of polymer product due to its dependence on monomer vapor pressure. In the nebulization technique for the preparation of polystyrene particles, the addition of various 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 polysiloxane-coated polystyrene with a core-shell structure.