Morphology and mechanical properties of styrene homoblends of methacrylate and sulfonate ionomers

Summary

Dynamic mechanical properties and morphology of homoblends of sulfonated polystyrene and poly(styrene-co-methacrylate) ionomers were investigated. While two tan δ peaks were found in the unblended ionomer samples, three tan δ peaks were observed for the homoblend. The peak at 152 °C is thought to be due to the matrix T _g, and those at 194 and 261 °C probably represent the glass transitions of cluster regions, containing methacrylate-rich multiplets and sulfonate-rich multiplets, respectively. In SAXS profile, only a very broad plateau-type feature was seen for the homoblend. This result implies either that the number density of the scattering centers at prevalent distances is low or that each scattering center has a different electron density. Thus we suggest that in the present study the multiplets of the homoblend consist of random mixtures of sulfonate and carboxylate groups.