Preparation and properties of chitosan/organic-modified attapulgite composite proton exchange membranes for fuel cell applications

The chitosan (CS) matrix-based composite proton exchange membranes (CS/QATP) were prepared by the incorporation of organic-modified attapulgite (QATP) into CS, through an organic-inorganic composite synthesis method. The QATP was obtained by the modification with silane coupling agent (octadecyldimethyl [3-trimethoxysilylpropyl] ammonium chloride). The morphology, crystallinity, thermal and mechanical property, dimensional stability, and proton conductivity of CS/QATP composite membranes were investigated. The compatibility and dispersibility of QATP in CS matrix were significantly improved with enhanced interfacial interaction. The dimensional and thermal stability of the CS/QATP composite membranes were improved compared with pure CS film, owing to good dispersion and lower water uptake. Especially, the composite membrane with 2 wt% QATP (CS/QATP-2) exhibits the highest mechanical strength and proton conductivity, which is much higher than pure CS film. These results indicated that CS/QATP composite membranes have a great potential for proton exchange membranes applications.