An approach to enhance through-thickness thermal conductivity of polymeric fiber composites

Thermal transport mechanisms are investigated and characterized when highly conductive fibers are embedded across the thickness of a three-dimensional polymer composite. Different approaches are explored to enhance out-of-plane thermal conductivity and address measurement issues associated with this class of composites. An experimental setup was designed, fabricated and validated to measure through-thickness thermal conductivity. A corresponding finite element model of the setup was developed to characterize and gain further understanding of the thermal field in the measurement cell. An approach in which a conductive coating is applied on the surface of the composite to improve the through-thickness thermal conductivity of composites containing a small percentage of conductive fibers in the thickness direction is explored. A parametric study revealed that the thickness of the coating and the distribution of the conductive fibers play a crucial role in augmenting the heat transfer across the thickness of the polymer composite.