Abstract: Ether nitrile co-polymers containing sulfonic acid groups, including wholly aromatic poly(aryl ether ether nitrile)s containing sulfonic acid groups (SPAEEN)s, and poly(phthalazinone ether ketone nitrile) co-polymers containing sulfonic acid groups (SPPEKN)s, intended for fuel cells applications as proton conducting membrane materials, were prepared.

Abstract: A method for the preparation of a cross-linked, sulfonated, proton exchange membrane for fuel cells, which includes: providing a sulfonated polymer, for example SPEEK; dissolving the sulfonated polymer in a polar casting solvent; adding at least one polyol cross-linking agent to obtain a solution, the cross-linking agent being added in a ratio of at least 1 polyol molecules per repeat unit of the sulfonated polymer to generate cross-linking; casting the solution to obtain the membrane; and curing the membrane.

Abstract: A novel class of proton exchange membrane materials, sulfonated poly(phthalazinones), were prepared by modification of poly(phthalazinone). Sulfonation reactions were conducted at room temperature using mixtures of 95-98% concentrated sulfuric acid and 27-33% fuming sulfuric acid with different acid ratios in order to get SPPEK with degree of sulfonation (DS) in the range of 0.6 to 1.0. The presence of sulfonic acid groups was confirmed by FT-IR analysis, and the DS and structures were characterized by NMR. The introduction of sulfonic groups into the polymer chains led to an increase in the glass transition temperature and a decrease in the decomposition temperature. Membrane films were cast from solution in N,N-dimethylformamide or N,N-dimethylacetamide. Water uptakes and swelling ratios of the membrane films increased with DS and sulfonated polymers with DS>1.2 were water soluble at 80° C. Proton conductivity increased with DS and temperature up to 95° C., reaching 10?2S/Cm.

Abstract: A new series of wholly aromatic poly(arylene ether ether ketone ketone)s containing pendant sulfonic acid groups (SPAEEKK) were conveniently prepared by potassium carbonate mediated nucleophilic polycondensation reactions of inexpensive commercially available monomers: 1,3-bis(4-fluorobenzoyl)benzene (BFBB), sodium 6,7-dihydroxy-2-naphthalenesulfonate (DHNS), and 4,4?-biphenol or hydroquinone in N-methyl-2-pyrrolidone (NMP) at 170° C. FT-IR and NMR were used to characterize the structures and the sulfonate or sulfonic acid contents (SC) of the polymers. Flexible membrane films were obtained by casting N,N-dimethylacetamide (DMAc) solutions of copolymers. Membrane films in acid form were then obtained by treating the sodium form membrane films in 2 N sulfuric acid at room temperature. Glass transition temperatures (Tgs) and decomposition temperatures (Tds) of SPAEEKKs in both sodium and acid forms were determined. Water uptake and swelling ratio values increased with SCs and temperatures.