PREPARATION AND PROPERTIES OF SULFONATED POLY(ARYLENE ETHER SULFONE)/SULFONATED POLYIMIDE BLEND PROTON EXCHANGE MEMBRANES

Abstract

A series of sulfonated poly(arylene ether sulfone)/sulfonated polyimide(SPAES/SPI)blend proton exchange membranes were prepared by solution casting method.The SEM results showed that no phase separation was found in the blend membranes,which indicated good miscibility between the two polymers.With the introduction of SPI,the blend membranes showed much higher stability in pure methanol than the corresponding SPAES membrane.The much lower methanol uptake of the blend membranes compared to that of Nafion 112 suggested the lower methanol permeability in the formers.The thermal stability of the blend membranes was similar with their pristine ones,and the desulfonation temperatures were above 290℃ .The blend membranes displayed much higher dimensional stability than the corresponding SPAES membrane.After aging at 130℃ for 200 h,the blend membranes maintained good mechanical properties,while the SPAES membrane was dissolved in the water.As a composite of two sulfonated polymers,the blend membranes maintained a high level of ion exchange capacity (IEC) and showed high proton conductivity.They displayed comparable proton conductivity with Nafion 112 at 80% relative humidity (RH ),and higher proton conductivity than that of Nafion 112 in water.