Flash DSC characterization of anisotropic thermal conductivity of hot-pressed carbon fiber/epoxy composites

Anisotropic thermal conductivities of thin films of thermal conductive composites are important properties in thermal management of micro-electronic devices. In Flash DSC measurements, we positioned the specimens in edge-on and flat-on configurations on the chip sensor, and characterized the corresponding in-plane and cross-plane thermal conductivities of epoxy composite hot-pressed films with 5 wt% and 10 wt% carbon fiber loadings. The results demonstrated that increasing the fiber content up to 10 wt% significantly enhances the thermal conductivity from the pure epoxy (0.21 ± 0.01) to the in-plane composite (1.7 ± 0.1) W·m -1 ·K -1 with an in-plane to cross-plane conductivity ratio of approximately 2.0. The results indicated that the hot-pressing processing makes the preferential alignment of carbon fibers along the in-plane direction to enhance the anisotropic thermal conductivity. This work extends the application of Flash DSC measurement to the anisotropic thermal conductivity characterization of microscale-thick composite films.