The fabrication of a boron nitride/ammonium polyphosphate skeleton based on ice template method for thermal conductive and flame retardant epoxy

Epoxy (EP) is widely used in the field of high-speed communication and microelectronics. However, its poor thermal conductivity and high flammability bury the hidden danger of fire accident. In this work, the hexagonal born nitride (h-BN) combined with ammonium polyphosphate (APP) constructs a three-dimensional skeleton (3D-BN) via bidirectional freezing technology. The 3D-BN skeleton is immersed into the EP matrix to obtain the EP/3D-BN composite, which is endowed with high thermal conductivity and flame retardancy. When the loading of hexagonal born nitride (h-BN) is 9.1 vol%, the thermal conductivity of EP/3D-BN3 composite reaches 1.67 W m-1 K-1, which is increased by 944 % compared with that of the control EP. The peak heat release rate (PHRR) and total heat release (THR) of EP/3D-BN3 are significantly reduced by 54 % and 34 % respectively. This EP/3DBN composite provides potential applications toward the industrial production for microelectronic devices.