An Experimental Investigation of Humidity and Temperature Effects on the Mechanical Properties of Persfluorosulfonic Acid Membrane

The mechanical properties of a perfluorosulfonic acid (PFSA) membrane have been investigated at different humidities and temperatures in a custom-designed environmental chamber. Tensile tests were conducted to determine Young’s modulus, the proportional limit stress (“yield strength”), break stress, and break strain. In-plane dimensional changes of the membrane at different temperature and humidities were also determined. The results indicate that Young’s modulus and the proportional limit stress of the PFSA membrane decrease as humidity and temperature increase. Higher temperature leads to lower break stress and higher break strain. However, humidity has little effect on the break stress and break strain. A nonparametric statistical analysis, Kruskal–Wallis test, is applied to the experimental results, which shows that the effects of temperature and humidity on Young’s modulus and proportional limit stress are statistically significant.