Preparation of boron nitride/graphene composite thermal conductive filler and study on flame retardant, thermal conductivity and insulation properties of epoxy resin composites

Abstract

<p indent="0mm">Epoxy resin is the most common thermosetting resin material at present. It has been widely used in various fields because of the characteristics such as excellent mechanical properties, electrical insulation, not easy to shrink and expand and corrosion resistance. At the same time, epoxy resin also has the disadvantages of high flammability and low thermal conductivity, and the electrical insulation may be damaged while improving the thermal conductivity of epoxy resin composites. Therefore, it is of great significance to develop new flame-retardant, heat-conducting and insulating epoxy resin composites. On the basis of using graphene as thermal conductive filler, boron nitride nanosheets with good electrical insulation performance are used to modify the surface of graphene. The obtained boron nitride/graphene composite thermal conductive filler is then added to the flame retardant epoxy resin, and the epoxy resin composite is prepared after hot pressing. The experimental results show that when the content of composite filler is 5 wt%, the thermal conductivity of epoxy resin composites prepared by hot pressing is <sc>0.931 W/(m K),</sc> which is 329.0% higher than that of pure epoxy resin; the volume resistivity is <sc>2.65×10¹⁴ Ω m,</sc> which is equivalent to pure epoxy resin, indicating good electrical insulation performance; The heat release of the composite was controlled and passed the V-0 level of vertical combustion, and the limiting oxygen index was 35.0%.