| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 100 === Abstract
The purpose of this study is to develop a polymer material containing sulfonic acid functional groups, which are further used as polyelectrolyte membrane in direct methanol fuel cells.
A novel new monomer BAPBDS-BMI containing sulfonic acid and bismaleimide groups was synthesized from 4,4’-bis(4-aminophenoxy)biphenyl (BAPB) and characterized. This new monomer was further reacted with benzoxazine and furan containing BPA-FBz monomer via Diels-Alder reaction to prepare a linear polymer BA-DA. This newly synthesized polymer containing benzoxazine and sulfonic acid groups was hot-pressed and cured into free standing flexible thin film. The curing process induces the ring opening reaction of benzoxazine groups, resulting in crosslinking effect in the polymer. The membranes are then further applied in fuel cell.
Although the degree of sulfonation of BA-DA membrane and commercialized membrane Nafion-117 is very close, but due to the crosslinking effect inside the BA-DA membrane, this membrane shows improved swelling property, dimensional stability and methanol permeability compared with Nafion-117.
The proton conductivity of BA-DA membrane is 5×10-2 S/cm, which is lower than that of Nafion-117 (9.1×10-2 S/cm), but the methanol permeability is 6 times higher than that of Nafion-117, and hence the selectivity is 3 times better than Nafion-117. For this reason, we predicted that BA-DA membrane will show better performance than Nafion-117 in DMFC.
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