Synthesis and Characterization of Polyimides Containing Pendent Benzimidazoles Groups for Proton Exchange Membrane

• Main Authors: REN-WUN Chen, 陳仁文
• Other Authors: Yaw-Terng Chern
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/nhre62

碩士 === 國立臺灣科技大學 === 化學工程系 === 105 === A series of copolyimides (PIs) with pendant benzimidazole had been synthesized. They had inherent viscosities in the range of 1.08~1.96 dL/g, and they could form tough and flexible films. The PIs exhibited high thermal stability with 10% decomposition temperature more than 500℃ in nitrogen, and their glass transition temperature is around 300℃. These films exhibited good mechanical properties with tensile stress exceeded 110 MPa. However, the mechanical properties of PI significantly decreased when phosphoric acid doping level increased. This situation can be improved via crosslinking reaction of methyl group, cross-linked PI would form close packing ,and it led to decrease of phosphoric acid doping level, but it could still maintain high proton conductivity. The proton conductivity of phosphoric acid doped PI was dependent on doping PA level and temperature. The proton conductivity of BPBI7mBI2PF0.5DMB0.5 and C5- BPBI7mBI2PF0.5DMB0.5were 77.3 and 68.5 mS/cm at 160℃, respectively. The proton conductivity of PI and C-PI were significantly higher than m-PBI (54.1 mS/cm). Thus, these polyimides (PIs) with pendant benzimidazole membranes could be the promising materials alternative to m-PBI membrane for medium-temperature fuel cells applications because of their high proton conductivity and good thermal stability.