Blending of styrene-block-butadiene-block styrene copolymer with sulfonated vinyl aromatic polymers

Different polymers containing sulfonic groups attached to the phenyl rings were prepared by sulfonation of polystyrene (PS) and styrene-block- (ethyle ne-co-1-butene)-block-styrene (SEBS). The sulfonation degree (SD) was varie d between 1 and 20mol% of the styrene units. Polyphase materials containing sulfonated units were prepared by blending styrene-block-butadiene-block-s tyrene (SBS), with both sulfonated PS and sulfonated SEES in a Brabender mi xer. Such a procedure was performed as an alternative route to direct sulfo nation of SBS which is actually not selective towards benzene rings because of the great reactivity of the double bonds in polybutadiene (PE) blocks t o sulfonation agents. Thermal and dynamic-mechanic analysis, together with morphology characterization of the blends, is consistent with obtaining par tially compatible blends characterized by higher T, of the polystyrene doma ins and improved thermal stability. (C) 2001 Society of Chemical Industry.