Nano-BN encapsulated micro-AlN as fillers for epoxy composites with high thermal conductivity and sufficient dielectric breakdown strength

In this work, the nano boron nitride (BN) was modified by poly(dopamine) and micro aluminium nitride (AlN) was modified by y-(2,3-epoxypropoxy)propytrimethoxysilane. Then the nano-BN was anchored though the chemical bonding reaction onto the surface of micro-AlN. The epoxy composites with the BN encapsulated AlN hybrid filler were prepared, showing a enhanced thermal conductivity of 1.449 W/(m-k), which is 946% higher than that of EP, 0.153 W/(m-k). And the results of dielectric breakdown experiments in high voltage at high frequency show that the sufficient dielectric strength with breakdown time of 72.6s, which is 256% higher than that of EP, 28.33s. This work provides a facile method for preparing high-performance epoxy composites with high thermal conductivity and sufficient dielectric breakdown strength.