STUDIES OF THE SOLUTION PROPERTIES OF SULFONATED-(STYRENE(ETHYRENE-CO-BUTYLENE)-STYRENE) BLOCK-COPOLYMER

The dilute solution properties of lightly sulfonated hydrogenated styr ene-butadiene-styrene block copolymer (S-SEBS) dissolved in tetrahydro funan (THF) were studied by viscometry. The ring conformation in dilut e regime can be deduced from the intrinsic viscosity data. It is belie ved that this special conformation results from the location of ionic group at both two-end blocks. The intermolecular aggregation can be ob served when the solutions undergo the freezing-thawing process in the same concentration region. The extent of aggregation is affected by th e freezing-thawing cycle times, water content in THF, and the counteri on radii, etc. The properties of the aggregation equilibrium are also discussed. (C) 1998 John Wiley & Sons, Inc.