Synergistic enhancement of anisotropic thermal transport flexible polymer composites filled with multi-layer graphene (mG) and mussel-inspiring modified hexagonal boron nitride (h-BN)

In this work, we presented novel cycloaliphatic epoxy resin composites filled with multi-layer graphene (mG)/hexagonal boron nitride (h-BN) with high thermal conductivity and good electrical insulating. Firstly, the h-BN platelets were modified by mussel-inspired method with dopamine chemistry to obtain the modified filler h-BN@PDA. And the attachment of polydopamine molecule improved the interfacial adhesion between polymer matrix and filler. Secondly, the mG with fixed content was mixed with h-BN@PDA and then the hybrid filler mG/h-BN@PDA was added to the cycloaliphatic epoxy resin to obtain the polymer composites. Because of the high aspect of the filler, low viscosity of the polymer matrix, and assistance of the gravity force, the hybrid filler would stack alignment. It was found that the hybridization of the filler and alignment of the hybrid filler resulted in the enhancement of properties of the composites such as the thermal decomposition, mechanical (tensile strength = 5.50 MPa), thermal (through-plane ∼ 1.27 W/m K, in-plane ∼ 1.31 W/m K) and electrical insulating (electrical conductivity < 1.5 × 10−10 S/cm) properties. The obtained composites could be applied in thermal management area.