Stress induced carbon fiber orientation for enhanced thermal conductivity of epoxy composites

Polymer composites that have high thermal conductivity have become one of the most promising solutions needed to satisfy the thermal management requirements for high-power electrical and electronic equipment. In this work, a strategy relying on aligning carbon fibers through the application of a stress field is proposed. Ultrahigh through-plane thermal conductive epoxy composites with carbon fiber networks have been prepared by in-situ solidification within an epoxy. The thermal conductivity of these epoxy composites reaches as high as 32.6 W m⁻¹ K⁻¹ at 46 wt percent (wt%) of carbon fibers, which is about 171 times that of the pure epoxy. The alignment condition for the carbon fibers for a carbon fiber composite in which stress has been applied and a blended carbon fiber composite are compared using micro compute tomography (micro-CT) and scanning electron microscopy (SEM). These epoxy composites display attractive thermal properties and provide a practical route to satisfy the thermal dissipation requirements raised by the development of modern electrical devices and systems.