Preparation and Characterization of Novel Bacterial Cellulose-based methanol-resistant Composite Membranes

• 1、Group of Microbiological Engineering and Industrial Biotechnology,College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620
• 2、College of Environmental Science & Engineering, Shanghai 201620

Abstract：In order to combine the good conductivity of Nafion with the excellent methanol-blocking capability of bacterial cellulose to produce a novel methanol-resistant proton exchange membrane, BC/Nafion/BC sandwich proton exchange composite membranes were prepared through attachment of bacterial cellulose membranes on two sides of a Nafion film. The molecular structure and thermal stability were studied by scanning electron microscopy and thermogravimetric analysis. Dimensional stability, proton conductivity and methanol permeability were studied for different sandwich membranes. The results showed that sandwich composite membranes had a compact structure and a good thermal stability. Compared with commercial Nafion films, the dimensional stability of sandwich composite membranes had been improved by 43%. In addition, along with the increase of temperature, proton conduction rate of the sandwich membranes rose apparently, which was slightly lower than that of the commercial Nafion films. However, the methanol permeability was obviously reduced from 10-6 to 10-7 , which means that methanol-resistant properties have been greatly improved. Single-cell performances showed that the membrane electrode assembly fabricated with the sandwich membranes reached the open-circuit voltages of 922 mV and the initial power densities of 7.2 mW cm-2, respectively. The results indicate that the BC/Nafion/BC sandwich composite membranes have a great potential if applied in direct methanol fuel cells as novel proton-conducting membranes.

Keywords： Composite material Bacterial cellulose Nafion Proton exchange membrane Sandwich membrane Methanol permeability Direct methanol fuel cell