SYNTHESIS AND PROPERTIES OF SULFONATED POLY(ETHER KETONE)S CONTAINING 3,5-DIMETHYL PHTHALAZINONE MOIETIES AS PROTON EXCHANGE MEMBRANE MATERIALS

Sulfonated poly(ether ketone)s containing 3,5-dimethyl phthalazinone moieties (SPPEK-DMs) with different degrees of sulfonation (DS) were synthesized via direct polycondensation from 4-(3,5-dimethyl-4-hydroxyphenyl)-2,3- phthalazinone, 4,4-difluorobenzophenone and 3,3-disulfonate-4,4-difluorobenzophenone. The chemical structure of SPPEK-DMs was characterized by FTIR and 1H-NMR. Thermal stability of SPPEK-DMs was characterized by the thermogravimetric analysis. The membranes prepared from SPPEK-DMs exhibited ion exchange capacities (IEC) ranging from 0.93 mmolg-1 to 1.86 mmolg-1. Water uptake, swelling, oxidative stability and methanol permeability of SPPEKDMs membranes were investigated. SPPEK-DMs membranes exhibited high oxidative stability. The methanol permeability values of SPPEK-DMs membranes were in the range 5.15 10-8-6.61 10-7 cm2s-1, which was much lower than those of Nafion117. The proton conductivity of SPPEK-DM40 membranes was 1.1 10-2 Scm-1 at 70C.