Effects of porous ePTFE content on the mechanical property of ePTFE/Nafion composite proton exchange membrane and the reinforced threshold

The effect of content of porous ePTFE on the mechanical property of the ePTFE/Nafion composite proton exchange membrane was carefully investigated. The results show there is a PTFE content threshold value (ca. 20.7%, volume fraction) beyond which the composite membrane could be reinforced. The tensile strength of the composite membrane goes up with the increasing of ePTFE content when the ePTFE content is greater than the threshold value, and decreases with growing ePTFE content when the ePTFE content does not reach the threshold value. The yield strength change of the composite membranes with the ePTFE content shows similar trend.