Preparation and Characterization of Blended Sulfonated Poly(arylene ether phosphine oxide)/Trisulfonated Poly(phthalazinone ether phosphine oxide) Proton Exchange Membranes

A series of blend membranes based on sulfonated poly(arylene ether phosphine oxide) (sPEPOF) and trisulfonated poly(phthalazinone ether phosphine oxide) (tsPPEPO) were prepared and studied. These blend membranes showed good compatibility, which might be ascribed to the excellent adhesive ability of the phosphine oxide groups and the strong intermolecular interaction. The properties of the blend membranes such as water uptake, swelling, proton conductivity, oxidative stability and methanol permeability were characterized in detail. The results showed that 7.5% weight content of blending tsPPEPO was beneficial to improve the blend membrane’s dimensional stability, oxidative stability, methanol resistance, and simultaneously keep considerable proton conductivity. For example, the blend membrane tsPPEPO-7.5 has an in-plane swelling of 8.2% and a through-plane swelling of 4.9% at 80°C, which are lower than those (14.1 and 13.0%, respectively) of the original sPEPOF membrane. At the same time, it has a conductivity of 0.080 S/cm, and its methanol permeability is about one-thirtieth of that of Nafion 117. Furthermore, the oxidative stability is also remarkably improved compared with that of the original sPEPOF membrane. Therefore, tsPPEPO is an ideal blend component for the achieved blend membranes, which exhibited excellent overall properties and application prospect.