A Concurrent Enhancement of Both In‐Plane and Through‐Plane Thermal Conductivity of Injection Molded Polycarbonate/Boron Nitride/Alumina Composites by Constructing a Dense Filler Packing Structure

Abstract In this work, a facile strategy is proposed to concurrently enhance both in‐plane and through‐plane thermal conductivity of injection molded polycarbonate (PC)‐based composites by constructing a dense filler packing structure with planar boron nitride (BN) and spherical alumina (Al 2 O 3 ) particles. The state of orientation of BN platelets is altered with the presence of Al 2 O 3 , which is favorable for improving both in‐plane and through‐plane thermal conductivity of subsequent moldings. Rheological analysis showed that the formation of intact thermal conductive pathways is crucial to the overall enhancement of thermal conductivity. Both in‐plane and through‐plane thermal conductivity of PC/BN(20 wt%)/Al 2 O 3 (40 wt%) composites reached as high as 1.52 and 1.09 W mK −1 , which are 485% and 474% higher than that of pure PC counterparts, respectively. Furthermore, the prepared samples demonstrated excellent electrical insulation and dielectric properties which show potential application in electronic and automotive industries.