Development of Proton Exchange Membranes Based on Chitosan Blended with Poly (2-Acrylamido-2-Methylpropane Sulfonic Acid) for Fuel Cells applications

Abstract

In this study case, the good film-forming and structural properties of chitosan (CTS) impelled us to employ them for developing polyelectrolyte membrane (PEMs). To functionalize the resultant PEMs, poly-2-acrylamido-2-methylpropane sulfonic acid (PAMPS) was blended with chitosan in different proportions. The structural and physical properties of CTS/PAMPS membranes were investigated using Raman scattering and FT-IR spectrometers, scanning electron microscope (SEM), thermos gravimetric analyzer (TGA), universal testing machine and water contact angle meter. Furthermore, water-uptake and ion exchange capacity (IEC), methanol permeability and efficiency of such membranes were measured. Ion exchange capacity of CTS/PAMPS membranes was increased with increasing the proportion of PAMPS to reach its maximum of 1.85 meq/g comparing with 0.9 meq/g for Nafion®117. Methanol permeability of the resultant blend-based membranes at CTS/PAMPS ratio of 2:1 was 9 × 10-7 cm2/sec comparing with 3.39 × 10-6 cm2/sec for Nafion®117. Moreover, CTS/PAMPS blend membranes exhibited efficiency factors higher than that of Nafion®117. Such results enhance the potential feasibility of CTS/PAMPS membranes for direct methanol fuel cell application.