Thermal Transformations in Extruded Saloplastic Polyelectrolyte Complexes

Extruded, salt-plasticized complexes of hydrated poly­(styrenesulfonate), PSS, and poly­(diallyldimethylammonium), PDADMA, were analyzed by differential scanning calorimetry and dynamic mechanical thermal analysis. Whereas the enthalpic signatures were weak, the latter technique revealed a strong transition in modulus, identified as a glass transition. The temperature of this transition, <i>T</i>_g, varied with deformation rate as expected from time/temperature superposition. <i>T</i>_g also decreased with increasing salt doping, which breaks ion pairing in the complexes, confirming the plasticizing effect of doping. Time, temperature, and salt concentration data were superposed to demonstrate the trends/equivalence of these three variables, and an empirical equation was used to connect them. Measurement time regimes were discussed with reference to the average lifetime of an ion pair