磺化聚醚酰亚胺/聚醚砜共混型质子交换膜的制备及其性能

以磺化聚醚酰亚胺(SPEI)和聚醚砜(PES)为原料, 采用溶液共混法成功制备出了SPEI/PES共混型质子交换膜,并经热重分析、AFM、SEM等对膜的结构和性能进行了表征. 结果表明, 共混膜较纯SPEI膜具有更高的热稳定性和较低的溶胀性; 在室温环境下, 共混膜在干态和湿态时均具有优异的机械性能; 与纯SPEI膜相比, 共混膜的形态结构更为致密, 这将有利于降低甲醇的渗透性. 采用交流阻抗法和隔膜扩散法分别考察了膜的质子传导性和阻醇性能, 对于共混质量比为50/50的膜来说, 其质子传导率达到了5.5 mS·cm-1的水平, 能满足质子交换膜的需求, 但其甲醇渗透系数明显降低, 仅为市用Nafion 112膜的5%, 这表明该共混膜有望作为一种新型的直接甲醇燃料电池用质子交换膜.

Preparation and Performances of Sulfonated Poly(ether imide) and Poly (ether sulfone) Blends for Proton Exchange Membrane

Sulfonated poly(ether imide) (SPEI) and poly(ether sulfone) (PES) blend membranes for application in the direct methanol fuel cells (DMFC) were successfully prepared by solution blend technique. The structure and performance of the obtained blend membranes were characterized using TGA, AFM, and SEM. The results showed that the blend membranes had higher thermal stability, lower swelling property, and good mechanical strength both in dry and wet states at ambient conditions. The morphology of blend membranes showed that its structure became more compact than that of pure SPEI, which might lead to decrease the methanol diffusion. The proton conductivity and the methanol permeability were determined by A.C. impedance spectrometry and diaphragm diffusion, respectively. The results showed that the SPEI/PES (mass ratio of 50/50) membrane still exhibited adequate conductivity (5.5 mS·cm-1) for application as proton exchange membranes. Meanwhile, the methanol permeability of the blend membranes decreased dramatically and was only 5% of that of Nafion 112 membrane. This tremendous reduction of methanol crossover could indicate a potential feasibility as a promising electrolyte for DMFC.