Material property models for polyethylene-based conductive blends suitable for PEM fuel cell bipolar plates

Abstract

Electrical and thermal conductivity models from Mamunya et al. and Kerner’s equation for elastic and flexural modulus have been applied to experimental data to assess model accuracies. Experimental data were gained from a previous study where polyethylene and carbon black, graphite and magnetite composites produced by injection and compression moulding were tested. The electrical conductivity modelling gave accurate fits to the data, though available data were limited and the thermal conductivity modelling produced good fits with R2 values greater than 0.93. The electrical and thermal model exponents were tuned for best fit and used to compare the modelling results with the literature and gain information about conduction mechanisms such as tunnelling and links, nodes and blobs and variations in local filler concentrations. A modified Kerner’s equation to effectively allow for filler type and variations in composite processing was used to improve upon the original equation which modelled modulus behaviour based on the pure matrix. The new equation proved to be a better predictor of elastic modulus than flexural modulus.