Chemical Degradation of Membrane Polymer Model Compounds under Simulated Fuel Cell Conditions

Abstract

Peroxide radical degradation is widely accepted as one of the key mechanisms by which PEM fuel cell membranes are eroded and ultimately fail. Testing of the mechanism of such failures is difficult, given the intractable nature of typical PEM polymers, and the low levels of degradation necessary to bring about failure. By use of low molecular weight model compounds, the mechanism of chemical degradation of both perfluorinated and hydrocarbon-based membranes can be simulated. These tests tell a clear story that common organic chemical reactivity patterns are followed, both polymer backbone carboxylic acid groups and side chain ether linkages are weak in perfluoro PEM materials, and that aromatic groups can be hydroxylated, and ether groups cleaved in hydrocarbon systems.