Patent ID: 6579948
Filing Date: 2003-06-17
Classification: C08F,Y10T

Abstract:
A semipermeable membrane produced from an unsulfonated block copolymer comprising polystyrene and polyisobutylene segments, said membrane comprising:a sulfonated block copolymer comprising poly (styrene-co-styrene sulfonic acid) segments and polyisobutylene segments, wherein said unsulfonated polystyrene and polyisobutylene block copolymer comprises polystyrene monomer in an amount of from 5% to 90% by weight of the total unsulfonated block copolymer, and wherein from 1 to 70 mole % of said polystyrene monomer in the unsulfonated polystyrene and polyisobutylene block copolymer is converted to said styrene sulfonic acid in the sulfonated block copolymer.