NON-AQUEOUS POLYSTYRENE DISPERSIONS - RADICAL DISPERSION POLYMERIZATION IN THE PRESENCE OF AB BLOCK COPOLYMERS OF POLYSTYRENE AND POLY(DIMETHYL SILOXANE)

Well defined AB block copolymers of polystyrene and poly(dimethyl siloxane) have been used as stabilizers in the dispersion polymerisation of styrene in n-alkanes. The dependences of the particle size and particle size distribution on the relative block lengths in the copolymer have been studied. From phase separation studies of polystyrene in n-alkanes, both in the presence and absence of AB block copolymer, the threshold molecular weight for precipitation has been determined. An understanding of the dispersion polymerization kinetics and the broad particle size distribution follows from the relatively high solubility of low molecular weight polystyrene in n-alkanes. © 1979.