Synthesis of Cellulose Acetate/Cross-Linked Poly(epichlorohydrin) Polymer Blend as Fuel Cell Anion Exchange Membrane

This study explores the development of an effective cellulose acetate (CA)-based material for use as an anion exchange membrane (AEM) in fuel cell applications. The combination of CA and poly(epichlorohydrin) (PECH) cross-linked with 1,4-diazabicyclo[2.2.2]octane (DABCO) was investigated with factors varied, namely, CA/PECH blend ratios, DABCO cross-linking mole ratio (RD/P), and trimethylamine functionalization time. Increasing the CA content improved the tensile strength (TS), while a higher PECH content raised the ion exchange capacity, water uptake (WU), average degree of swelling (DSAve), and strain rate. Setting RD/P = 0.5 enhanced TS, elongation at break, WU, and DSAve, exhibited by improved stress–strain values and reduced hydrophysical properties in the 50:50 blend, which are attributed to successful cross-linking. The measured ionic conductivity was 32.7 mS cm–1 at 30 °C and peaked at 60 °C with a value of 51.1 mS cm–1. Thermogravimetric analysis revealed that the AEM remained thermally stable under typical operating conditions. An accelerated stability test of the AEM in 1 M KOH/D2O at 60 °C showed insignificant degradation, indicating superb chemical stability. Lastly, the fuel cell test at 30 °C measured a peak power density of 13.3 mW cm–2 at a current density of 24.7 mA cm–2. A high open circuit potential value of 1.02 V was recorded, suggesting that the voltage loss due to gas crossover is negligible. These findings indicate that the fabricated CA/PECH membranes have promising potential applications in AEM fuel cells.