Highly thermally conductive epoxy composites with anti-friction performance achieved by carbon nanofibers assisted graphene nanoplatelets assembly

Thermally conductive epoxy composites have a broad range of applications in many fields relating to microelectronic devices and encapsulating materials of high-power electrical appliance. However, it is still a challenge to effectively fabricate thermally conductive epoxy composite materials that have various excellent comprehensive properties. In this work, a simple suction filtration method is developed to construct the self-supported framework of graphene nanoplatelets (GNPs) and carbon nanofibers (CNFs), and then epoxy is impregnated into the framework to prepare the composites. The morphological characterizations show that one dimensional CNFs exhibit the “supporting” effect between the parallelly arranged GNP layers in axial direction and the “bridging” effect between adjacent GNP aggregates in radial direction, and the self-supported framework is maintained in the epoxy composites. The highest thermal conductivities are 3.74 W/m·K in radial direction and 3.28 W/m·K in axial direction, at filler contents of 13.09 and 14.49 wt%, respectively, which are 1770% and 1540% higher than that of the pure epoxy. Further results show that the composite samples have high storage modulus, enhanced thermal resistance, and improved anti-friction performance, all of them ensure that the epoxy composites can be used as the materials of the components and parts of the electrical appliance toward continuous loading, vibration, and large heat dissipation.