Proton exchange composite membranes from blends of brominated and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Abstract

AbstractNew composite proton exchange membrane was prepared by mixing a 1‐methyl‐2‐pyrrolidone (NMP) solution of sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO) in sodium form and brominated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (BPPO) for hydrophilic‐hydrophobic balance, then casting the solution as a thin film, evaporating the solvent, and treating the membrane with aqueous hydrochloric acid. The resulting membranes were subsequently characterized using FTIR‐ATR, SEM‐EDXA, and TGA instrumentation as well as measurements of basic properties such as ion exchange capacity (IEC), water uptake, proton conductivity, methanol permeability, and single cell performance. Water uptake, IEC, proton conductivity, and methanol permeability all increased with a corresponding increase of SPPO content. By properly compromising the conductivity and methanol permeability, membranes with 60–80 wt % SPPO content exhibited comparable proton conductivity to that of Nafion® 117, with only half the methanol permeability, thereby demonstrating higher single cell performance. The membranes developed in this study could thus be a suitable candidate electrolyte for proton exchange membrane fuel cells (PEMFCs). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012