International Journal of Hydrogen Energy, Vol.37, No.15, 11383-11393, 2012
Self-crosslinked anion exchange membranes by bromination of benzylmethyl-containing poly(sulfone)s for direct methanol fuel cells
A series of novel anion exchange membranes based on poly(arylene ether sulfone) were fabricated. And the synthesized 1, 1, 2, 3, 3-pentamethylguanidine was used as a hydrophilic group. Bromination reaction rather than chloromethylation was used for the preparation of target conductive polymers. Fourier transform infrared spectroscopy (FTIR), H-1 NMR and mass spectrometry (MS) were used to characterize the as-synthesized polymers. The ratio of hydrophilic to hydrophobic monomers was varied to study the structure-property of the membranes. The performance of the membrane with both hydrophilic/hydrophobic segments was improved over the membrane with sole hydrophilic segments. The self-crosslinlcing structure of the as-prepared membranes is partly responsible for their very low methanol permeability with the minimum of 1.02 x 10(-9) cm(-2).S-1 at 30 degrees C and insolubility in organic solvents considered. The structural dependence of water uptake is in the range of 25-87%. The as-prepared membranes did not suffer from serious membrane swelling. The ionic exchange capacity (IEC) reached a maximum of 1.21 mmol.g(-1). The ionic conductivity of the membrane in deionized water is 6.00 and 13.00 x 10(-2) S.cm(-1) at 30 and 80 degrees C respectively. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Anion exchange membranes;Direct methanol fuel cells;Poly(arylene ether sulfone);Self-crosslinking structure