Physical and mechanical properties of graphene and h-Boron nitride reinforced hybrid aerospace grade epoxy nanocomposites

Varying graphene nanoplatelet (GNP) and hexagonal boron nitride (h-BN) based fillers were integrated to an aerospace grade epoxy resin typically used as matrix to obtain or repair structural parts of aerospace platforms. The threeroll milling approach was used for this purpose. Five cycles were performed for the mixing while the gap between rollers was 50 mu m. Microstructure and thermal properties of the nanocomposites were studied. Moreover, mechanical and transport (electrical as well as thermal) performances were investigated. Results show that certain fillers yield multifunctional properties, that is, enhanced flexural strength by up to 69% in combination with high electrical conductivities with orders of magnitude of approximately 103 S= m and improved thermal conductivities up to 9.3%. For instance, the hybrid nanocomposite sample produced with 0.5 wt% GNP and 0.5 wt% h-BN added to the epoxy matrix exhibits an electrical conductivity which increased 108 fold, a flexural strength increased by 69% and thermal conductivity increased by 7% in comparison the neat epoxy. Hence, in this study it was demonstrated that these properties can be engineered and tuned effectively for aerospace applications like lightweight avionic chassis which have specific requirements like thermal and electric conductivity which naturally leads to the possible usage of GNP and h-BN in an epoxy. Correspondingly, presented results are of relevance for novel thermal interface materials with tailored electrical properties.