Surfactantless synthesis of amphiphilic cationic block copolymers

摘要

The present invention is directed to a method of producing an amphiphilic block copolymer, including the steps of:(1) preparing a first aqueous polymerization medium which is comprised of (a) 4-vinylpyridine,(b) a trithiocarbonate RAFT agent, and an emulsifier, wherein the emulsifier is prepared in-situ within the aqueous polymerization medium by the reaction of a latent surfactant with a surfactant activator;(2) polymerizing the 4-vinylpyridine within the first aqueous polymerization medium in the presence of a first free radical initiator to produce a poly(4-vinylpyridine);(3) protonating the poly(4-vinylpyridine) to form a protonated poly(4-vinylpyridine) RAFT macroinitiator;(4) preparing a second aqueous polymerization medium which is comprised of the protonated poly(4-vinylpyridine) RAFT macroinitiator and a monomer containing ethylenic unsaturation but is exclusive of a surfactant; and(5) polymerizing the protonated poly(4-vinylpyridine) RAFT macroinitiator and monomer containing ethylenic unsaturation within the second aqueous medium in the presence of a second free radical initiator and a temperature less than 100° C. to produce an amphiphilic block copolymer of the 4-vinylpyridine and monomer containing ethylenic unsaturation.