Conductive polymer composites with high electrical and mechanical properties are in demand for bipolar plates of phosphoric acid fuel cells (PAFC). In this study, composites based on natural graphite/fluorinated ethylene propylene (FEP) and different ratios of carbon black are mixed and hot formed into bars. The overall content of natural graphite is replaced by carbon black (0.2 wt% to 3.0 wt%). It is found that the addition of carbon black reduces electrical resistivity and density. The density of composite materials added with carbon black 3.0 wt% is 2.168 g/cm3, which is 0.017 g/cm3 less than that of non-additive composites. In-plane electrical resistivity is 7.68 μΩm and through-plane electrical resistivity is 27.66 μΩm. Compared with non-additive composites, in-plane electrical resistivity decreases by 95.7 % and through-plane decreases by 95.9 %. Also, the bending strength is about 30 % improved when carbon black is added at 2.0 wt% compared to non-additive cases. The decrease of electrical resistivity of composites is estimated to stem from the carbon black, which is a conductive material located between melted FEP and acts a path for electrons; the increasing mechanical properties are estimated to result from carbon black filling up pores in the composites.

Abstract
1.서 론
2. 실험방법
    2.1 제조 방법
    2.2 원료 분석
    2.3 부피밀도
    2.4 미세구조 분석
    2.5 굽힘 강도 측정 및 평가
    2.6 전기비저항 측정
3. 결과 및 고찰
    3.1 원료 분석
    3.2 부피밀도
    3.3 미세조직 관찰
    3.4 굽힘 강도
    3.5 전기 비저항 분석
4.결 론
References

• 김효창(금오공과대학교 신소재공학과) | Hyo-Chang Kim (School of Materials Science and Engineering, Kumoh National Institute of Technology)
• 이상민(금오공과대학교 신소재연구소) | Sang-Min Lee (Advanced Material Research Center, Kumoh National Institute of Technology)
• 남기법(금오공과대학교 신소재연구소) | Gibeop Nam (Advanced Material Research Center, Kumoh National Institute of Technology)
• 노재승(금오공과대학교 신소재공학과) | Jae-Seung Roh (School of Materials Science and Engineering, Kumoh National Institute of Technology) Corresponding author