DABCO‐functionalized polysulfones as anion‐exchange membranes for fuel cell applications: Effect of crosslinking

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 55; no. 17; pp. 1326 - 1336
• Main Authors: Teresa Pérez‐Prior, María, Ureña, Nieves, Tannenberg, Monika, del Río, Carmen, Levenfeld, Belén
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.09.2017
• Subjects: Anion exchanging; Chlorides; Crosslinking; DABCO; Dimensional stability; Electrolytic cells; Fuel cells; Fuels; Ion currents; Ion exchange; Ions; Membranes; Molten salt electrolytes; polysulfone; Solid electrolytes; Stability analysis; Tensile strength; thermal properties; Thermal stability
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.24390

ABSTRACT A series of DABCO‐functionalized polysulfones were synthesized and characterized. The effect that crosslinking has on the membrane properties containing different degrees of functionalization was evaluated. These polymers showed good thermal stability below the fuel cell operation temperature, T < 100 °C, reflected by the TOD, TFD, and thermal durability. The water uptake increased as the percentage of DABCO groups increased and the crosslinked membranes showed lower capacity to absorb water than the non‐crosslinked ones favoring thus the dimensional stability of the first ones. Membranes in the chloride form containing low degree of functionalization exhibited the highest tensile strength values. The ionic conductivity of non‐crosslinked membranes varied as a function of the functionalization degree until a value of around 100% achieving a maximum value at 86%. However, the crosslinked ones showed satisfactory ionic conductivities for values higher than 100%. The behavior of these polymeric materials in alkaline solutions revealed a great alkaline stability necessary to be used as solid electrolytes in fuel cells. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1326–1336 Anion‐exchange membranes containing pendant ammonium groups were synthesized from polysulfone by chrolomethylation followed by nucleophilic substitution reaction with DABCO. Given that DABCO has two nitrogen atoms which can be tethered to the polymer, crosslinked polymers were also prepared. The thermal and alkaline stability of the resulting membranes as well as their electrochemical properties made these materials susceptible to be used as solid electrolytes in fuel cells.