Novel Characteristics of Polystyrene Microsphere Prepared by Microemulsion Polymerization

摘要

Microspheres prepared by microemulsion polymerization contain only one or at most a few macromolecular chains which adopt special conformation: single chain is highly compact, while the whole structure of the microsphere is loose. This special conformation leads to some physical properties of this product different from that of ordinary polymer This paper reports apparent differences in thermal behaviors between micro-PS (produced by microemulsion polymerization) and o-PS (ordinary polystyrene) during the DSC scan(fig.l). Micro-PS displayed two exothermic peaks near 107℃ and 157℃ during the first scan. In the subsequent scan, both of them disappeared and only one glass transition similar to o-PS was shown. r-PS (obtained by dissolving micro-PS in toluene and reprecipitating from methanol) displayed the same DSC curve as o-PS. Pure micro-PS was obtained by washing and kept its virgin conformation which was formed during the polymerization.