A simple heat treatment to prepare covalently crosslinked membranes from sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) for application in fuel cells

For application in fuel cells, a series of low-cost proton exchange membranes with covalently crosslinking structure were prepared from sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) just through a heat treatment. The crosslinking reaction was verified and investigated in detail. The crosslinking degree could be controlled by adjusting the time or temperature for heat treatment. With a proton conductivity of 0.128 S cm−1 and tensile strength of 52.8 MPa, the optimum membrane showed a maxim power density of 0.893 W cm−2 while that of Nafion® 112 is 0.602 W cm−2 in a single cell test at 60 °C. In view of the competitive properties with Nafion® series, the crosslinked membranes are qualified for a potential application in fuel cells.