Composite proton exchange membrane of cellulose triacetate polymer integrated with polyacrylic acid and triazole based copolymer for balanced proton conduction and methanol permeability

Abstract BACKGROUND Proton exchange membranes (PEMs) could prompt proton transport with long‐term oxidative and hydrolytic durability with little methanol crossover under humidified conditions. Cellulose triacetate (CTA)‐based PEMs were fabricated by reinforcing with 4 wt.% of polyacrylic acid (PAA) and polymerized triazole (PTZA) combination of acrylic acid/triazole acrylate copolymer. RESULTS The presence of PAA and PTZA copolymer in the CTA membrane was confirmed using Fourier transform infrared spectroscopy and X‐ray diffraction. The variations of proton conductivity, methanol crossover and water uptake of the PTZA copolymer‐reinforced CTA matrix were evaluated. Higher proton conductivity of 2.313 × 10 −4 S cm −1 and minimal methanol permeability of 1.773 × 10 −7 cm 2 s −1 were obtained for the CTA/PTZA–20 membrane compared to a pristine CTA membrane. Furthermore, the oxidative tolerability was about 99.6% for CTA/PAA membrane, and hydrolytic stability was 97.78% for the CTA/PTZA–20 membrane, higher than that of the pristine CTA membrane. CONCLUSIONS The increase in proton conduction compared to pristine CTA membrane could be attributed to the presence of triazole moiety, which acts as a proton facilitator in the conduction process. Additionally, an increase in hydrolytic stability, oxidative tolerability and lower methanol crossover results indicated that the PTZA copolymer‐reinforced CTA PEMs have potential for use in fuel cell applications. © 2021 Society of Chemical Industry (SCI).