An Investigation of Chitosan-Grafted-Poly(vinyl alcohol) as an Electrolyte Membrane

The membrane of chitosan-grafted-poly(vinyl alcohol)/poly(vinyl alcohol) (CS-g-PVA/PVA) was investigated along with chitosan (CS), PVA, CS/PVA, and Nafion 117 membranes for transport properties of water and methanol, mechanical properties, and ionic conductivity. The ionic conductivity sigma, of the crosslinked CS-g-PVA/PVA membrane was about 4.37 mS cm(-1) and the methanol permeability, P-s, was 1.8 x 10(-7) cm(2)s(-1). These gave the selectivity, sigma/P-s, of 23.95 mS.s.cm(-3) compared with 16.35 mS.s.cm(-3) of Nafion 117 membrane. The conductivity of the crosslinked CS-g-PVA/PVA membrane was greater than others including Nafion 117 when the membranes were saturated with methanol solution of which concentration was greater than 20%. This fact and that the mechanical properties of the wet crosslinked CS-g-PVA/PVA membrane were comparable to those of other membranes made it a promising material to be used as an electrolyte membrane in a direct methanol fuel cell.