CHARGE-MOSAIC MEMBRANE FROM GAMMA-IRRADIATED POLY(STYRENE-BUTADIENE-4-VINYLPYRIDINE) TRIBLOCK COPOLYMER

Poly(styrene-butadiene-4-vinylpyridine) triblock copolymers were prepared from styrene (S), butadiene (B), and 4-vinylpyridine (P) by sequential anionic polymerization with n-butyllithium as initiator and benzene as solvent. The triblock copolymer was characterizated by gel-permeation chromatography (GPC), transmission electron microscopy (TEM), and viscoelastic spectrometry. Films of the triblock copolymer cast from solution in mixtures of chloroform and n-butyraldehyde were subjected to gamma-ray irradiation to form cross-linked networks. Cationic and anionic groups were introduced by sulfonation and quaternization to obtain charge-mosaic membranes. The resulting membrane had substantial cation-exchange and anion-exchange capacities. The membranes were very permeable to electrolyte (J(KCl) = 2.10 X 10(-8) mol/cm2 s). (C) 1993 John Wiley & Sons, Inc.