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Study on Graphite/Polypropylene/Liquid Crystalline Polymer Composite for a Bipolar Plate of Polymer Electrolyte Membrane Fuel Cell

고분자 전해질막 수소 연료 전지 분리판 용 흑연/폴리프로필렌/액정고분자 복합 재료의 특성에 관한 연구

  • Dhungana, Biraj (Division of Advanced Materials Science & Engineering, Kongju National University) ;
  • Son, Younggon (Division of Advanced Materials Science & Engineering, Kongju National University)
  • Received : 2015.04.16
  • Accepted : 2015.05.07
  • Published : 2015.05.31

Abstract

We investigated mechanical, rheological and electrical properties of graphite/PP/LCP composites for a bipolar plate of the polymer electrolyte membrane fuel cell. The composites containing very low molecular weighted PP showed much higher electrical conductivity compared with other thermoplastics. This was attributed to the enhanced dispersion of graphite particles due to the low viscosity of the PP. The conductivity of the composites was increased in a great extent by incorporation of small amount of carbon nano tube (CNT). However, the acid treated CNT which contains oxygen atoms did not increase the conductivity of the composite. From this result, it is concluded that the CNT has higher affinity with non polar polymer. The composite with low molecular weighted PP provided good processability so that the composites can be processed by an injection molding while the mechanical strength is deficient compared to other polymers. In order to reinforce the low mechanical property, LCP/PP was used as a binder and the graphite/PP/LCP composite showed the higher conductivity and moderate mechanical strength maintaining suitable processability.

고분자 전해질 막 연료전지의 분리판 용 흑연/폴리프로필렌(PP)/액정고분자 (LCP) 복합소재의 기계적, 유변학 특성 및 전기전도도에 관하여 연구하였다. 저분자량 PP를 바인더로 사용하는 경우 다른 열가소성 고분자와 비교하여 상당히 높은 전기 전도도를 보임을 확인하였는데 이는 점도가 낮은 PP에 의해 흑연 입자의 분산이 향상되어 나타난 결과임을 확인할 수 있었다. 또한 탄소나노튜브를 소량 첨가하면 복합재료의 전기전도도가 크게 증가하였고 산처리를 하여 산소 관능기를 포함한 탄소나노튜브를 첨가했을 때에는 전기전도도의 증가가 거의 없었다. 이로부터 탄소나노튜브는 비극성 고분자와 친화도가 높음을 알 수 있었다. 저분자량 PP를 바인더로 사용하였을 때는 복합재료의 점도가 사출성형이 가능할 정도로 낮은 것을 관찰할 수 있었다. 그러나 기계적인 강도는 다른 고분자에 비해 현저히 낮았다. 이를 보강하기 위하여 LCP를 혼합하여 복합재료를 제조한 결과 전반적인 물성 밸런스가 잘 맞는 복합재료를 얻을 수 있었다.

Keywords

References

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