Synthesis of novel sulfonated poly(arylene ether)s containing a tetra-trifluoromethyl side chain and multi-phenyl for proton exchange membrane fuel cell application?

RSC Advances Pub Date: 2017-06-29 DOI: 10.1039/C7RA04731B

Abstract

Herein, a series of novel sulfonated poly(arylene ether)s consisting of tetra-trifluoromethyl-substituted multi-phenyl was synthesized via polycondensation, and post-sulfonation was carried out through chlorosulfonic acid to obtain sulfonated polymers possessing ion exchange capacities ranging from 1.27 to 2.53 mmol g?1. 1H NMR and FTIR spectroscopy were applied to confirm the structure and composition of the sulfonated polymers. The membranes exhibited considerable dimensional stability (with 3.1–27.8% change in length; 17–56.5% change in thickness at 80 °C) and excellent oxidative stability (weight remained higher than 97%). The mechanical properties of the membranes demonstrated good tensile strength on account of the highly rigid multi-phenylated backbone, and Young's modulus ranged from 0.65 to 0.88 GPa. The proton conductivities of the membranes ranged from 0.03 to 0.24 S cm?1 at 80 °C under 95% RH, which were comparable to or higher than those of Nafion 211. The morphology of the membranes demonstrated a clear hydrophilic/hydrophobic phase separation with spherical ionic clusters in the size range of 5–20 nm. SFC2-2.53 demonstrated a high current density (around 1800 mA cm?2 at 0.6 V) and the maximum power density of 1.41 W cm?2 for the fuel cell performance. The results indicated that SFC2 would be a good candidate for proton exchange membranes in fuel cell applications.

Graphical abstract: Synthesis of novel sulfonated poly(arylene ether)s containing a tetra-trifluoromethyl side chain and multi-phenyl for proton exchange membrane fuel cell application
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