Synthesis and Characterization of Star-Branched Ionomers Composed of Sulfonated Polystyrene Outer Blocks and Elastomeric Inner Blocks

Star-branched ionomers composed of short sulfonated polystyrene outer blocks and hydrogenated butadiene or isoprene inner blocks, with narrow molecular weight distributions (13C and 1H NMR and FT-IR revealed \u3e 99% hydrogenation using p-toluene sulfonyl hydrazide in refluxing toluene. Titration of the sulfonic acid groups revealed \u3e 85% sulfonation of the styrene units by acetyl sulfate in methylene chloride. Characterization of the final product and the various intermediates was carried out by GPC, DSC, FT-IR, and 13C NMR. A summary of the developmental work leading to these new materials is presented