Mono-dispersed cross-linked polystyrene micro-spheres prepared by seed swelling polymerization method

Abstract

A two-step swelling procedure was adopted to synthesize mono-dispersed and highly cross-linked poly (St-divinylbenzene) particles with PSt micro-spheres (1.80 ?m in diameter). The PSt micro-spheres were prepared by a dispersion polymerization method and used as seeds. The effects of monomer concentration, ratio of ethanol to water, swelling reagents, crosslinking reagents, swelling temperature and agitation speed on particle size were investigated in detail. The morphologies and size distributions of these micro-spheres were examined by SEM and particle size analysis (PSA). The T_g of the micro-spheres was measured by DSC. The results indicate that the particles (6.20 ?m in diameter) exhibit excellent mono dispersed property and high crosslinking degree when the concentration of the swelling reagent was 25%, the concentration of the crosslinking reagents was 23%, the swelling temperature was 30°C and the stirring speed was 150 r/min.

Keywords

dispersion polymerization / seed swelling polymerization / mono-dispersed crosslinking polystyrene micro-spheres