Synthesis of fluorinated polymer electrolyte membranes by radiation-induced grafting and atom transfer radical polymerization techniques

放射線グラフト及びATRP重合法によるフッ素系高分子電解質膜の合成

Zhai, M.; 長谷川 伸; Chen, J.; 前川 康成

Zhai, M.; Hasegawa, Shin; Chen, J.; Maekawa, Yasunari

本研究では、化学安定性の高い直接メタノール燃料電池(DMFC)用電解質膜を開発するため放射線によるフッ素系モノマーであるBrTFFをETFEフィルムへグラフト重合し、次いで、ATRP法によるグラフト重合及びスルホン化反応によって導電性高分子電解質膜の合成に成功した。従来法によるスチレングラフトETFE電解質膜と比較して、本研究で合成した電解質膜は導電性基が均一に分布してあり、高いイオン交換能とプロトン導電性があることがわかった。

To develop a highly chemicallly stable polymer electrolyte membrane for appilcation in a direct methanol fuel cell, a fluorinated monomer, Bromotetrafluoroethyl trifluorovinyl ether (BrTFF), was grafted firstly into poly(ethylene-co-tetrafluoroethylene) (ETFE) membrane by irradiation. Further, a new-type polymer electrolyte membrane was synthesized by atom transfer radical polymerization of styrene into ETFE-graft-polyBrTFF membrane followed by sulfonation. The bromine groups in ETFE-graft-polyBrTFF membrane functioned as initiators, and a Cu-based catalytic system of Cu(I)Br and bipyridyl (bpy) was empolyed for the ATRP. It was found that styrene was grafted homogeneously into ETFE-graft-polyBrTFF membrane and the prepared polymer electrolyte membrane have higher ion exchange capacity (IEC) and proton conductivity than that of normal ETFE-g-PSSA membrane.