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Polyvinylidene fluoride/poly(ethylene terephthalate) conductive composites for proton exchange membrane fuel cell bipolar plates: Crystallization, structure, and through-plane electrical resistivity

Authors

  • Jianbin Song,

    1. Department of Chemical Engineering, Laval University, Quebec, Canada G1A 0A6
    2. State Key Laboratory of Materials-Oriented Chemical Engineering, Department of Material Science and Technology, Nanjing University of Technology, Nanjing 210009, China
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  • Frej Mighri,

    Corresponding author
    1. Department of Chemical Engineering, Laval University, Quebec, Canada G1A 0A6
    2. CREPEC, Center for Applied Research on Polymers and Composites, Quebec, Canada
    • Department of Chemical Engineering, Laval University, Quebec, Canada G1A 0A6
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  • Abdellah Ajji,

    1. CREPEC, Center for Applied Research on Polymers and Composites, Quebec, Canada
    2. Department of Chemical Engineering, Ecole Polytechnique of Montreal, Quebec, Canada H3T 1J4
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  • Chunhua Lu

    1. State Key Laboratory of Materials-Oriented Chemical Engineering, Department of Material Science and Technology, Nanjing University of Technology, Nanjing 210009, China
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Abstract

Polyvinylidene fluoride/poly(ethylene terephthalate) (PVDF/PET)-based composites for proton exchange membrane fuel cell bipolar plates (BPs) were prepared at different crystallization temperatures and characterized by X-ray diffraction, differential scanning calorimetry, and resistivity setup. Composite conductivity was made possible by using a mixture of carbon black (CB) and graphite (GR). To improve composite processability, its viscosity was reduced by adding a small amount of cyclic butylene terephthalate (c-BT) oligomer and thermoplastic polyolefin elastomer. In the PVDF/PET-based composite, it was found that PVDF phase could crystallize easily but PET crystallization was difficult. Because of the CB/GR additives, the formed crystals in PVDF/PET phases had a poor perfection degree and showed a lower melting temperature when compared with pure PVDF and PET. It was observed that PET nucleation was accelerated but not that of PVDF. According to through-plane resistivity results, composite crystallization temperature range was divided into two parts (below/above 170°C), in which a different variation behavior of through-plane resistivity was observed. It has been proved that the resistivity was mainly governed by the network of CB/GR developed inside the PET phase, and decreasing the crystallinity of PET led to a decrease of through-plane resistivity, which is desirable for BPs. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

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