Phase dominance, multiple glass transitions, and apparent activation energies in some poly (styrene‐co‐alkali methacrylate) ionomers

The high‐temperature dispersions occurring in some poly (styrene‐co‐alkali methacrylate) ionomers are investigated by dynamic mechanical thermal analysis as a function of ion content. The heights and areas of the loss modulus peaks associated with these dispersions suggest that the ionic “cluster” phase becomes the dominant and perhaps even continuous phase above an ion concentration of ca. 6 mol %. Apparent activation energies of these high‐temperature transitions support the phase‐separated cluster model and indicate that the dispersions are true glass transitions.