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Fabrication and characterization of bipolar plates of vinyl ester resin/graphite-based composite for polymer electrolyte membrane fuel cells

The lightweight economical bipolar plates for proton exchange membrane fuel cells were fabricated by using vinyl ester resin as matrix material, graphite powder as reinforcement and conducting polymer as additive. Effects of various contents of graphite and its particle size on electrical conductivity, physical and mechanical properties of the composite were investigated. The optimum composition of composite plates was determined at 55% graphite, 40% resin and 5% poly(1,4-phenylene sulphide) based on measurements of physical, electrical and mechanical properties with various graphite contents. The plate molded with 2.93 mm thickness gives density of 1.81 g cm−3 and compressive strength of 73 MPa, which is in consonance with reported standard. Thermogravimetric analysis–differential thermal analysis–derivative thermogravimetry of the composite was carried out in air atmosphere to find out mode of degradation and basis of its stability. The study reveals that composite is less stable than resin and graphite, but much more stable than operational fuel cell which works at 80–100°C.