AIN particles/BN whiskers co-doped epoxy composites modified with polydopamine with high thermal conductivity

In this work, aluminum nitride particles (AlN) and boron nitride whiskers (BNw) were surface-functionalized by polydopamine, and then novel composites were prepared by co-doping. By observing with transmission electron microscopy, we clearly saw that the surfaces of AlN and BNw were successfully coated with a thin polydopamine coating. This is beneficial to enhance the interface interaction between the filler and the resin matrix, improve the interfacial compatibility, and evenly distribute the thermally conductive filler in the resin matrix. The co-doping of the two thermally conductive fillers increases the chance of contact between the filler and the filler, and reduces the interfacial thermal resistance, thereby forming a thermal conduction network more efficiently. The results show that at a frequency of 1 MHz at room temperature, the dielectric constant of 30 wt%AlN@PDA/6 wt%BNw@PDA/EP composites is 4.74 and the dielectric loss tangent is 0.0171. Its thermal conductivity is 0.40 W/(m·K), the glass transition temperature reaches 250.22 °C, the impact strength reaches 6.89 kJ m−2, and the breakdown field is 10.93 kV/mm.