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Innovative Highly Out-of-Plane Thermally Conductive Fibre Reinforced Plastic



The advantages of Fibre Reinforced Plastics (FRP) over conventional metallic materials are their lightweight, high strength and non-corrosive properties. Nevertheless, one major disadvantage is the low out-of-plane thermal conductivity (TC) of FRP which limits their application where heat has to be dissipated through the thickness such as heat exchangers or electronic enclosures. Research in the last years at the Institut für Textiltechnik (ITA) of RWTH Aachen University, Germany, has shown that the TC of FRP can be increased one order and more using ultra high modulus pitch-based carbon fibres. These fibres have an axial TC in the range between 120 and 900 Wm-1K-1 whereas copper – one of the highest thermally conductive materials – has one of 400 Wm-1K-1. Unfortunately the ultrahigh modulus of these fibres comes along with very high brittleness which hinders the use in many textile processes. Nevertheless, ITA has developed processes to manufacture composite parts based on 2D and 3D preforms as well as on 2D and 3D prepregs [1]. An innovative invention from ITA increases the out-of-plane TC of FRP from below 1 Wm-1K-1 to 26 Wm-1K-1 using pitch-based carbon fibres. The clue is the integration of the highly brittle pitch-based carbon fibres with an E-modulus of 950 GPa into a honey comb structure. Hence, 100 % of the fibres can be oriented in out-of-plane direction to guide heat from one side to the other. The invention is under patent process.

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