PRODUCTION OF POLYSTYRENE PARTICLES VIA AEROSOLIZATION

Aerosolization of polystyrene solutions followed by drying in a tubula r furnace produced submicron-sized polystyrene particles. Characteriza tion using x-ray diffraction, scanning electron microscopy (SEM), and infrared spectroscopy (FT-IR) revealed that the particles were amorpho us, spherical, and free of residual solvent. The average particle size and size distribution varied with furnace temperature, the initial po lystyrene solution concentration, and solvent type. The particles' BET -based specific surface area depended upon these parameters as well as the carrier gas flow rate. Analysis of the competing rates of convect ion, solvent evaporation, droplet collisions, and polymer diffusion he lp to rationalize the results. The dependence of the solvent evaporati on rate on temperature controls the particle diameter, but droplet coa lescence cannot be ignored. Long residence times and high furnace temp eratures softened the particles; after filtration, polymer diffusion b etween solid particles produced visual evidence of partial coalescence . (C) 1995 John Wiley & Sons, Inc.