Synthesis and properties of novel H-bonded composite membranes from sulfonated poly(phthalazinone ether)s for PEMFC

In this work, sulfonated poly(phthalazinone ether)s (SPPENK, SPPESK and SPPBEK) were synthesized by direct aromatic nucleophilic polycondensation reaction. H-bonded composite membranes were prepared from SPPENK, SPPESK and SPPBEK, respectively, and polyetherimide (PEI). Both of compounds were dissolved in N-methylpyrrolidone (NMP), and tough membranes were obtained by casting from NMP solution with 9:1 mass ratio of sulfonated poly(phthalazinone ether)s/PEI. These H-bonded composite membranes all showed better thermal, oxidative and mechanical stabilities than corresponding pure sulfonated polymers membranes. The H-bonded composite membranes had high proton conductive ranging from 0.02 to 0.06 S/cm at 95 °C. All membranes showed an increase in proton conductivities with temperature elevation. The swelling ratio of H-bonded composite membranes was lower than that of pure membranes.