Measuring thermal conductivities of anisotropic synthetic graphite–liquid crystal polymer composites

Abstract In this study, synthetic graphite particles were added to a liquid crystal polymer and the resulting composites were tested for both the through‐plane thermal conductivity k_thru and the in‐plane thermal conductivity k_in using the transient plane source method. The end use application for these composites is in fuel cell bipolar plate fabrication. The goal of this work was to expand upon a previously developed simple empirical model for the in‐plane thermal conductivity, which is easily measured with the transient plane source method. The results show that the square root of the product of the through‐plane and in‐plane thermal conductivities is an exponential function of the volume percent of filler, ϕ. As the through‐plane thermal conductivity of these composites is accurately predicted with a modified Nielsen model, this empirical relationship can be used to estimate in‐plane thermal conductivities for a range of applications. POLYM. COMPOS., 27:388–394, 2006. © 2006 Society of Plastics Engineers