Synthesis and characterization of ionic conducting sulfonated polybenzimidazoles

International audienceBy copolymn. of the disodium-2,2'-disulfonate-4,4'-oxydibenzoic acid (SODBA), the 4,4'-oxybis(benzoic acid) (OBBA) with the bis 3,4-(diaminophenyl)sulfone (BDAPS), a series of high mol. wt. sulfonated polybenzimidazoles (sPBI) were prepd. by varying the ratio of monomers SODBA/OBBA. Polymers with ion exchange capacity (IEC) ranging from 0 to 3.2 meqH+/g were obtained. The chem. structure of the sPBI was confirmed by NMR, Fourier-transform infra-red (FTIR). Although the sPBI display a very poor soly. in org. solvents, they are, in the ammonium salt form, sol. in polar aprotic solvents such as DMF, NMP, or DMSO. Tough and ductile membranes from soln. casting method were prepd. The water uptake and the ionic cond. were detd. at 30 and 90