Synthesis and Characterization of Polyelectrolyte Complex N-Succinylchitosan-chitosan for Proton Exchange Membranes

Synthesis of acid-base complex membrane is one of method to improve the proton conductivity in proton exchange membrane for fuel cell applications. In this study, acid-base complex membrane was synthesized based on N-succinylchitosan-chitosan complexes. The N-succinylchitosan was blended with chitosan in acetic acid at various substitution degree of N-succinylchitosan with weight ratio of N-succinylchitosan of 80% w/w. The acid-base complex membranes were cast from the polymer solution and dried by evaporation. The properties of the membranes such as water uptake, ion exchange capacity, proton conductivity, and mechanical strength were analyzed. It was observed that the increase of substitution degree of N-succinylchitosan tends to increase the proton conductivity. The optimum performance of membrane unit is attained by the substitution degree of N-succinylchitosan of 0.72, which is reflected by its ion exchange capacity of 3.45 meq/g and proton conductivity of 7.35 × 10-2 S cm-1, respectively. Blending of N-succinylchitosan and chitosan also improved the mechanical strength of the membranes. These results imply that this type of polyelectrolyte complex membrane is a good candidate for proton exchange membrane in fuel cell applications.