Composite proton exchange membranes produced using chitosan and kaolin solvent-free fluid

Abstract

Abstract In this study, composite membranes produced by combining both biopolymer chitosan (CS) and kaolin solvent-free fluid (kaolin-SF) were used as substitutes for the electrolyte membranes in direct-methanol fuel cells. To improve the interfacial morphologies between organic and inorganic substances, kaolin-SF was prepared using the ion exchange method. Subsequently, kaolin-SF of various doping proportions was mixed with CS crosslinked with sulfuric acid to produce thin membranes. The results of heat exhaustion and scanning electron microscope image analysis indicated that kaolin-SF was successfully doped into the CS polymer substrates, and this addition enhanced the thermal stability and mechanical properties of the CS polymer substrates. As long as the concentration of kaolin-SF was below 5 wt.%, the water absorption rate and proton conductivity of the CS/kaolin-SF composite membranes increased along with the kaolin-SF content. These results indicate that CS/kaolin-SF composite membranes are suitable for practical applications.