Effects of Low Matrix Glass Transition Temperature on the Cluster Formation of Ionomers Having Two Ion Pairs per Ionic Repeat Unit

Abstract

The dynamic mechanical properties and morphology of novel ethyl acrylate ionomers, poly-(ethyl acrylate-co-itaconate) [P(EA-co-ITA)], were investigated. It was found that the P(EA-co-ITA) ionomers showed a well-developed cluster loss tangent peak, which was not seen in poly(styrene-coitaconate) ionomers. This is probably due to the low matrix Tg of the PEA ionomers, which allows ITA units to form a significant number of multiplets, leading to high clustering. The large difference in the matrix and cluster T g's was also observed; this is mainly due to two factors. First, the presence of two ion pairs in an ionic repeat unit makes ion-hopping difficult, resulting in higher cluster Tg. Second, the clustering induced by the low matrix Tg naturally increases the cluster Tg. It was also found that the clustering degree was weaker for the itaconate ionomers than for the acrylate ionomers, which is probably due to the fact that the presence of two ion pairs in one ITA unit is more effective in stiffening polymer chains compared to the case of acrylate ionomers. In an SAXS study, an ionomer peak was observed, and the position of the peak shifted to slightly higher angle with increasing ion content, implying that more multiplets form with increasing ion content.

Polymer Thermoplastic Proton Conductors Based on PPO and PS Ionomer Blends

“…Dynamic mechanical analysis (DMA) reveals that, depending on the ionic group content, the relaxation associated to the glass transition temperature shifts to higher temperatures, increases the width of the relaxation, or even shows a phase separation behavior 24,25. This fact can be observed in the Figure 2, where loss tangent is plotted against temperature.…”

Proton mobility in hydrated sulfonated polystyrene

“…Investigations dealing with hydration and swelling of membranes have been carried out to analyze the influence of hydration conditions on transport properties of polymer [22][23][24]. In ionic polymers, hydration makes that adjacent clusters to be interconnected through channels that enhances ion and water transport [25][26][27][28].…”

Dynamic mechanical properties of polystyrene ionomers containing both carboxylate and sulfonate anionic groups

“…It should be mentioned that at a cluster glass transition, ion hopping is operative,6, 9, 13–19 which is directly related with the strength of interactions between ion pairs. If the size of the multiplets of the PSMA‐SS ionomer is larger, due to the presence of more ion pairs per multiplet, than those of the PSS and PSMA ionomers, the ion pairs in the multiplet of the PSMA‐SS ionomer will experience difficulty in hopping.…”