Synergetic enhancement of thermal conductivity by constructing BN and AlN hybrid network in epoxy matrix

Thermal management has developed into a severe issue with the evolution of electronics. The construction of effectively thermal conduction pathways in the matrix is crucial for highly thermal conductive composites. In this work, a unique thermal conductive channel in the epoxy matrix had been established with hybridizing hexagonal boron nitride (BN) sheets and aluminum nitride (AlN) particles through a solution mixture and hot-pressing method. Synergetic enhancement of thermal conductivity was observed between BN and AlN fillers owing to the better dispersion of hybrid fillers, which created more pathways for phonon transport. With 40 vol% hybrid BN-AlN filler contents, the thermal conductivity of EP composite reached 2.4 Wm−1 K−1, eightfold increasing over the pristine epoxy matrix and two times to that of single BN or AlN filling composite. Moreover, the thermal conductivity of hybrid composite was further improved by more than 10% through the surface treatment of fillers with silane couple agents owing to the enhancement of interaction in composites. This study is of critical importance for composites used in electronics and electric equipment.