Nonaqueous Polystyrene Dispersions Stabilized by Silicone Block Copolymers: Anionic Dispersion Polymerization and Dispersion Properties
Anionic polymerization techniques have been used to prepare AB block copolymers of polystyrene and poly (dimethyl siloxane) having well defined molecular weight and composition, and narrow molecular weight distribution. Anionic dispersion polymerizations of styrene in aliphatic hydrocarbons were performed in the presence of such block copolymers, giving polymer particles stabilized by surface layers of silicone. The effects of varying the polymerization conditions, and the type and concentration of block copolymer, were studied. The conformation of the silicone chains as a function of molecular weight was estimated from data for particle diameter, by transmission electron microscopy, and for the thickness of the surface layer, by viscosity measurements. The results suggest that the silicone chains are extended over a random coil conformation.
KeywordsBlock Copolymer Aliphatic Hydrocarbon Dispersion Polymerization Narrow Molecular Weight Distribution Styrene Monomer
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