Internal oriented strategy of the hBN composite resin with enhanced in-plane or through-plane thermal conductivity via 3D printing

In this work, we report a facile preparation of the composite resin with significantly enhanced high in-plane or through-plane thermal conductivity via controlling the layer thickness of digital light processing (DLP) 3D printing less than the lateral size of hBN. The thermal conductivity of the composite resin reaches up to 7.962 W∙m−1∙K−1 along the oriented direction at the content of 30 wt% hBN flakes with a lateral size of 25 μm under the 3D printing layer thickness of 15 μm, which is about 44 times greater than that of the pure resin. It is found that a lower thickness of the printing layer leads to a higher degree of the hBN flake orientation and higher thermal conductivity of the composite resin. Inspired by this method, the thermal conductivity prediction model based on the process parameters is established and has a higher accuracy than the traditional model. In addition, the 3D printed composite resin exhibits excellent thermostability, low water absorption and volume shrinkage, favorable mechanical properties, and great dielectric properties. This approach provides a new vision for the application of 3D printing in thermal management.