Enhanced thermal conductivity of polycarbonate-based composites by constructing a dense filler packing structure consisting of hybrid boron nitride and flake graphite

In this work, thermally conductive yet electrically insulative polycarbonate (PC)-based composites with hybrid boron nitride (BN) and flake graphite (Gt) network structure were prepared by high shear injection molding process. A synergy in improving the thermal conductivity of PC was observed with the hybrid loading of BN and Gt. Results showed that the in-plane thermal conductivity of PC/BN 30 wt%/Gt 16 wt% composite reached as high as 4.08 W/mK, which were 189% and 358% higher than that of PC/BN 30 wt% and PC/Gt 16 wt% composites, respectively. The preferred orientation of planar fillers and interconnection between added fillers were indispensable to the significant increase of in-plane thermal conductivity, as corroborated by X-ray diffraction, rheology and scanning electron microscope observations. Moreover, the electrical resistivity of PC/BN 30 wt%/Gt composites was higher than 10(14) omega cm, which shows potential application in thermal management areas such as advanced electronic devices and battery units among others.