Structure-property relationships in novel ionomers

Abstract

It is observed for the first time that telechelic ionomers based on sulfonated polyisobutylene exhibit primary and secondary SAXS peaks when the molecular weight distribution is narrow (Mw/Mn ca. 1.15). These SAXS peaks are interpreted as due to non-global lamellar or cylindrical ionic domain order. The non-global ordering strongly affects the tensile and dynamic mechanical properties of the ionomer. This effect is attributed to local ionic phase continuity and the concept of restriction of chain motion by the ionic domain. Triblock copolymer ionomers from t-butyl methacrylate (tBMA) end blocks and polybutadiene or tapered poly(styrenelbutadienel styrene) (tSBS) mid blocks exhibit complex SAXS patterns indicating dispersed spheroidal ionic end block domains in the matrix. TEM shows that ionization of the 9 mol % PtBMA-PBD triblock produces a morphological transformation from unoriented rodlike domains to ionic spheroids.