▎ 摘　　要

NOVELTY - A heat-resistant composite dielectric material comprises an epoxy resin as substrate, and a benzoxazine additive curing, and boron nitride nanosheets (BNNS) and fluorinated graphene as filler, by stripping hexagonal-boron nitride into boron nitride nano-sheet and mixing with the fluorinated graphene filler to form anisotropic arrangement, and forming a continuous heat-conducting path and high heat-conducting network. USE - Heat-resistant composite dielectric material. ADVANTAGE - The heat-resistant composite dielectric material has excellent high dielectric characteristics and high thermal conductivity, and is prepared economically by simple process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the heat-resistant composite dielectric, which involves mixing (i) hexagonal-boron nitride powder with 5 mol/L sodium hydroxide solution, pouring it into a round bottom flask and ultrasonically-stirring for 6 hours, performing hydrothermal reaction at 180 degrees C for 24 hours to obtain hydroxyl-functionalized boron nitride nanosheets, washing the boron nitride nanosheets with deionized water until they are neutral, drying, and adding (ii) predetermined content of boron nitride nanosheets and fluorinated graphene to benzoxazine and epoxy resin, and adding a mixed solvent, stirring for 30 minutes and adding mixed liquid of prepared curing agent and accelerator, and stirring for 1 hour, rotating (iii) the obtained product from step (ii) at 80 degrees C to remove the solvent, putting the obtained glue into a vacuum oven at 60 degrees C for vacuum degassing for 30 minutes, and pouring it into the preheated mold, vacuum degassing at 60 degrees C for 30 minutes and curing (iv) products obtained in step (iii) at 120 degrees C for 2 hours and at 130 degrees C for 2 hours, and cooling to room temperature.