Polymer electrolyte membranes prepared by EB-crosslinking of sulfonated poly(ether ether ketone) with 1,4-butanediol

Crosslinked sulfonated poly(ether ether ketone) (SPEEK) membranes were prepared through the electron beam (EB)-irradiation crosslinking of SPEEK/1,4-butanediol under various irradiation conditions and used as a proton exchange membrane (PEM) for fuel cell applications. The crosslinked membranes were characterized by gel fraction, a universal testing machine (UTM), dynamic mechanical analysis (DMA), and small-angle X-ray scattering (SAXS). The gel fraction of the crosslinked membranes was used to estimate the degree of crosslinking, and the gel fraction was found to be increased with an increase of the crosslinker content and EB-absorbed dose. The UTM results indicate that a brittle EB-crosslinked membrane becomes more flexible with an increase in the crosslinker content. The DMA results show that the EB-crosslinked membranes have well-developed ionic aggregation regions and the cluster T-g of membranes decrease with an increase in the 1,4-butanediol crosslinker content. The SAXS results show that the Bragg and persistence distance of crosslinked membranes increase with an increase in the crosslinker content. The proton conductivities of the EB-crosslinked membranes were more than 9 x 10(-2) S/cm. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41760.