Preparation and Characterization of Graft Copolymer/$TiO_2$ Nanocomposite Polymer Electrolyte Membranes

가지형 공중합체/$TiO_2$ 나노복합 고분자 전해질막의 제조 및 분석

  • Koh, Jong-Kwan (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Roh, Dong-Kyu (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Patel, Rajkumar (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Shul, Yong-Gun (Department of Chemical and Biomolecular Engineering, Yonsei University) ;
  • Kim, Jong-Hak (Department of Chemical and Biomolecular Engineering, Yonsei University)
  • Received : 2009.12.02
  • Accepted : 2009.12.29
  • Published : 2010.03.30

Abstract

A graft copolymer, i.e. poly(vinylidene fluoride-co-chlorotrifluoroethylene )-g-poly(styrene sulfonic acid) (P(VDF-co-CTFE)-g-PSSA) with 47 wt% of PSSA was synthesized via atom transfer radical polymerization (ATRP). This copolymer was combined with titanium isopropoxide (TTIP) to produce graft copolymer/$TiO_2$ nanocomposite membranes via sol-gel process. $TiO_2$ precursor (TTIP) was selectively incorporated into the hydrophilic PSSA domains of the graft copolymer and grown to form $TiO_2$ nanoparticles, as confirmed by FT-IR and UV-visible spectroscopy. Water uptake and ion exchange capacity (IEC) decreased with TTIP contents due to the decrease in number of sulfonic acid in the membranes. At 5 wt% of TTIP, the mechanical properties of membranes increased while maintaining the proton conductivity.

원자전달 라디칼 중합을 이용하여 poly(styrene sulfonic acid) 47 wt%를 가진 poly(vinylidene fluoride-co-chlorotrifluoroethylene)-g-poly(styrene sulfonic acid) (P(VDF-co-CTFE)-g-PSSA) 가지형 공중합체를 합성하였다. 티타늄 아이소프로폭사이드(TTIP)와 가지형 공중합체를 졸-겔 공정을 통하여 $TiO_2$/가지형 공중합체 복합막을 제조하였다. TTIP는 가지형 공중합체의 친수성을 가진 PSSA 영역에만 선택적으로 결합하였으며 그곳에 $TiO_2$ 나노 입자가 형성되어 성장하였다. 이와 같은 결과를 적외선과 자외선 분광학으로 확인할 수 있다. 함수량과 이온 교환 능력 (IEC)는 TTIP의 함량에 따라 감소하였고 이것은 막이 가진 술폰산의 수가 감소하기 때문이었다. TTIP가 5 중량%일 때, 막의 기계적 강도는 증가하고 수소이온 전도도도 유지되었다.

Keywords

References

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