Cross-linked membranes with a macromolecular cross-linker for direct methanolfuelcells

Abstract

With the goal of reducing water swelling and methanol permeability in sulfonated proton exchange membranes (PEM), bromomethylated poly(ether ether ketone) was synthesized and used as a macromolecular cross-linker. The cross-linking reaction was performed at 195 °C for 5 h and resulted in cross-linked membranes with high cross-linked density. Compared to the pristine membrane, the cross-linked membranes displayed greatly reduced water uptake and methanol permeability. Other properties of the cross-linked membranes, including proton conductivity, mechanical properties, and oxidative stability, were also investigated and compared with the pristine membrane. All the results indicated that the novel macromolecular cross-linker and the resulting cross-linked membranes are promising for fuel cell applications.