Patent ID: 6111025
Filing Date: 2000-08-29
Classification: C08F

Abstract:
A process for preparing a block copolymer comprising a hydrophobic block (A) comprising one or more hydrophobic monomers and a hydrophilic block (B) comprising one or more hydrophilic monomers, said process comprising:(a) first polymerizing at least one hydrophobic monomer comprising at least one vinyl aromatic monomer to prepare a hydrophobic block as an end block, using a free radical polymerization process,wherein a stable free radical agent is employed during the polymerization, thereby preserving a stabilized active polymerization site on the hydrophobic block;(b) thereafter adding at least one hydrophilic monomer to the stabilized active hydrophobic block of (a); and(c) further reacting the mixture of (b) to effect polymerization of said hydrophilic monomer, thereby preparing a hydrophilic block;wherein the polymerization of the hydrophilic monomer is conducted in an amidic solvent in which the hydrophobic block and the at least one hydrophilic monomer are sufficiently soluble to permit polymerization;wherein the at least one hydrophilic monomer comprises a mixture of 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof and N,N-dimethylacrylamide.