The effects of matrix glass transition temperature and polarity, and ionic group spacers on ion aggregation in styrene ionomers /

Matrix glass transition temperature depression through internal plasticization of a styrene-sodium methacrylate ionomer resulted in enhanced clustering at low plasticization levels (up to ca. 20 mole%). At higher plasticization levels, ion aggregation was strongly disrupted. Matrix polarity effects were studied by nitrating the styrene units of the same ionomer. A sample with a relaxed dielectric constant comparable to acrylate polymers showed no decrease in clustering. Similarly, plasticization with nitrobenzene resulted in typical nonpolar diluent behavior. Polarity was, therefore, not a significant parameter affecting ion aggregation. New styrene copolymers with substituents R = $-$(CH$ sb2$)$ sb{ rm n}$COOMe (n = 1, 5, 10) or R = $-$O(CH$ sb2$)$ sb{ rm n}$COOMe (n = 1, 4, 10) in the para- position were synthesized, to form a systematic investigation of ionic group spacing effects on the dynamic mechanical properties of ionomers. The results were rationalized in terms of bulkiness and rigidity of the units supporting the ionic groups, and polymer backbone immobilization efficiency. Ion solvation effects were also suggested for the ether derivatives