Anhydrous Crosslinked Polymer Electrolyte Membranes Based On ABA Triblock Copolymer

ABA 트리블록 공중합체를 이용한 무가습 가교형 고분자 전해질막

  • Kim, Jong-Hak (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Koh, Jong-Kwan (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Lee, Do-Kyoung (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Roh, Dong-Kyu (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • ShuI, Yong-Gun (Department of Chemical and Biomolecular Engineering, Yonsei University)
  • 김종학 (연세대학교 화공생명공학과) ;
  • 고종관 (연세대학교 화공생명공학과) ;
  • 이도경 (연세대학교 화공생명공학과) ;
  • 노동규 (연세대학교 화공생명공학과) ;
  • 설용건 (연세대학교 화공생명공학과)
  • Published : 2009.09.30

Abstract

ABA type triblock copolymer of poly(hydroxyl ethyl acrylate )-b-polystyrene-b-poly(hydroxyl ethyl acrylate), i.e. PHEA-b-PS-b-PHEA, was synthesized throughatom transfer radical polymerization (ATRP). This block copolymer was thermally crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification between the -OH groups of PHEA in block copolymer and the -COOH groups of IDA. Upon doping with ${H_3}{PO_4}$ to form imidazole-${H_3}{PO_4}$ complexes, the proton conductivity of membranes continuously increased with increasing ${H_3}{PO_4}$ content. The PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ polymer membrane with [HEA]:[IDA]:[${H_3}{PO_4}$]=3:4:4 exhibited a maximum proton conductivity of 0.01 S/cm at $100^{\circ}C$ under anhydrous conditions. Thermal gravimetric analysis (TGA) shows that the PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ complex membranes were thermally stable up to $350^{\circ}C$, indicating their applicability in fuel cells.

원자전달 라디칼 중합을 이용하여 poly(hydroxyl ethyl acrylate)-b-polystyrene-b-poIy(hydroxyl ethyl acrylate) (PHEA-b-PS-b-PHEA) 트리블록 공중합체를 합성하였다. 이렇게 합성된 PHEA-b-PS-b-PHEA블록 공중합체의 -OH 그룹과 이미다졸 디카르복실릭산(IDA)의 -COOH 그룹과의 에스테르 반응에 의하여 가교된 전해질막을 제조하였다. 인산(${H_3}{PO_4}$)을 도핑하여 이미다졸-인산 착체를 형성한 결과, 인산 함량이 증가함에 따라 고분자 전해질막의 수소 이온 전도도가 증가하였다. 특히 [HEA]:[IDA]:[${H_3}{PO_4}$]=3:4:4의 조성을 갖는 PHEA-b-PS-b-PHEA/IDA/${H_3}{PO_4}$ 고분자 전해질막은 $100^{\circ}C$의 비가습 조건에서 최대 0.01 S/cm의 수소이온 전도도를 나타내었다. 열분석 결과(TGA) 전해질막은 $350^{\circ}C$의 고온까지 열적으로 안정함을 확인하여 연료전지에 적용이 가능함을 보여주었다.

Keywords

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