Three-dimensional skeleton assembled by carbon nanotubes/boron nitride as filler in epoxy for thermal management materials with high thermal conductivity and electrical insulation

Due to high aspect ratio, excellent thermal conductivity, and electrical insulation, boron nitride exhibits a great potential in the field of electronic packaging. However, its longitudinal thermal conductivity is far poor than horizontal thermal conductivity, which limits its application in a wider field. Herein, a three-dimensional (3D) network structure is constructed by coating boron nitride nanosheets/carbon nanotubes on foam skeleton derived from the commercial polyurethane (PU) (3D BNNS/CNTs). The in-situ grown CNTs on the surface of BNNS produce an interconnected network structure. The resultant 3D skeleton coupled with cross-linked BNNS/ CNTs endows it with excellent thermal and mechanical properties. After curing with epoxy resin, the optimized 3D BNNS/CNTs15 %/Epoxy composite obtains a high thermal conductivity of 1.49 W m-1 K-1 at a low loading of 20 wt%, which achieves a thermal conductivity enhancement of 1046 % compared to neat epoxy resin. Meanwhile, the synthesized 3D BNNS/CNTs15 %/Epoxy composite maintains a high electrical resistivity above 1010 omega m, high elastic modulus of 1.0 GPa and tensile stress of 35 MPa. Thus, this strategy may offer a new insight for constructing advanced packaging materials with excellent thermal and mechanical performances for electronic device.