Effect of hygrothermal ageing on the tensile and fracture response of a fuel cell membrane

Nafion is a polymer electrolyte membrane used as proton-conducting medium for a polymer electrolyte fuel cell. Since the membrane is a very critical component of the fuel cell, its operational durability becomes highly significant to the fuel cell performance. In general, a low temperature fuel cell operates under 80 °C and 90% RH (relative humidity) and since the Nafion is very sensitive to these operating conditions its mechanical properties vary drastically, leading to premature mechanical failure of the membrane over a period of time. In a first of its kind, this paper focuses on the fracture response of the membrane that is externally pretreated with respect to different hygrothermal conditions. The membrane is also tested for its tensile strength. The results obtained from this study suggest a very interesting phenomenon. The data show that though there is no meaningful trend in the results obtained through tensile tests, fracture tests show a remarkable difference in the fracture energy of the specimens that are subjected to different hygrothermal conditions.