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SynopsisThe physical properties of a new class of ionomers comprising a semirigid polyphenylene ether backbone were investigated. The material was studied principally in the form of films of ca. 150 pm micrometers in thickness. The study focused on material of 600 equivalent weight. Torsion pendulum results showed a significant increase in the glass transition temperature of the ionomer relative to that of its ester precursor but gave no evidence of ionic clustering. Stress-strain studies performed both in water and in 20% KOH solution at 80°C indicated that the mechanical properties of the material remain stable under these conditions. Differential scanning calorimetry was used to investigate both the high temperature behavior and the water uptake of the ionomer films. The behavior of this ionomer at high temperature and in a n alkaline solution is of particular interest in view of the possible use of these films as separators in a n alkaline electrolysis cell.

SynopsisThe sorption and transport properties of newly developed aromatic carboxylate polymers have been investigated in the context of their application as membrane separators for water electrolyzers. Conductance measurements of aromatic carboxylates of various equivalent weights have been performed as a function of current density, temperature, and electrolyte environment. Results have been compared with those for Nafion 117. The sorption results in dilute and concentrated solution show large water and electrolyte uptake for the aromatic carboxylate films. Furthermore, relatively large sodium ion selfdiffusion coefficients have been found in both dilute and concentrated solution environments. The results of these measurements are characteristic of microporous films. The dc conductance behavior of the aromatic carboxylate ionomers is quite different from that found for nonporous 1150 equivalent weight Nafion membranes. This difference is caused primarily by the microporous structure of the aromatic carboxylates, which results in large membrane specific conductances.

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