Block copolymer synthesis by a miniemulsion stable free radical polymerization process

The ultimate success of living-radical polymerizations will depend on wheth er they can be used to make materials with unique properties in an economic al and acceptable manufacturing process. We report a major step in this dir ection for the SFRP process by demonstrating that a miniemulsion process ca n be used to polymerize monomers to high conversion with a high degree of l ivingness and that this process can be used to synthesize block copolymers. The key to the polymerizations is the use of a nitroxide-terminated oligom er to initiate the miniemulsions. Miniemulsions are performed at 135 degree sC to greater than 99% conversion to give polystyrenes with polydispersitie s between 1.15 and 1.25. Chain extension studies show these materials to ha ve a high degree of livingness. Reaction of these polystyrene latexes with n-butyl acrylate lead to the first block copolymers completely made under S FRP miniemulsion conditions.