Block Copolymer Synthesis by a Miniemulsion Stable Free Radical Polymerization Process

Abstract

The ultimate success of living-radical polymerizations will depend on whether they can be used to make materials with unique properties in an economical and acceptable manufacturing process. We report a major step in this direction for the SFRP process by demonstrating that a miniemulsion process can be used to polymerize monomers to high conversion with a high degree of livingness and that this process can be used to synthesize block copolymers. The key to the polymerizations is the use of a nitroxide-terminated oligomer to initiate the miniemulsions. Miniemulsions are performed at 135 °C to greater than 99% conversion to give polystyrenes with polydispersities between 1.15 and 1.25. Chain extension studies show these materials to have a high degree of livingness. Reaction of these polystyrene latexes with n-butyl acrylate lead to the first block copolymers completely made under SFRP miniemulsion conditions.