▎ 摘　　要

NOVELTY - Method for preparing boron nitride graphene oxide polyimide composite material, involves (a) preparing graphene oxide, (b) preparing a boron nitride nanosheet, (c) ultrasonic treating the obtained graphene oxide and boron nitride nanosheet to obtain boron nitride graphene oxide filler, (d) adding a diamine monomer to the reaction system obtained in step (c) under the protection of nitrogen atmosphere, adding tetracarboxylic dianhydride within 0.5-1 hour, uniformly stirring at room temperature for 8-16 hours to obtain a mixed solution of boron nitride graphene oxide polyamic acid, and (e) casting the obtained mixed solution on a glass plate, baking in oven at 120-180degrees Celsius until the solvent is volatilized completely, placing the mixture in muffle furnace, maintaining the temperature at 280-330degrees Celsius for 1-3 hours, naturally cooling to room temperature, and stripping the sample from glass plate to obtain composite film. USE - Method for preparing boron nitride graphene oxide polyimide composite material. ADVANTAGE - The method regulates the microstructure of the filler particles by simultaneously regulating the ratio of boron nitride and graphene oxide, thus regulating the thermal conductivity of the composite material. The obtained composite material has a thermal conductivity of greater than 0.6 W/mK, and a resistivity of greater than 1 x 1011 Omegam. DETAILED DESCRIPTION - Method for preparing boron nitride graphene oxide polyimide composite material, involves (a) adding phosphorus flake graphite, concentrated sulfuric acid and concentrated phosphoric acid to a flask, adding potassium permanganate to the system while stirring, continuously stirring for 10-40 minutes, placing the system in a water bath at 40-80degrees Celsius, stirring at a speed of 200-1000 rpm for 8-16 hours, pouring the obtained mixed solution after reacting into deionized water and concentrated sulfuric acid with volume ratio of 1:1, uniformly stirring the mixed solution at a stirring speed of 30-200 rpm for 3-10 minutes, adding 30 wt.% hydrogen peroxide to the system while stirring until the mixed solution becomes golden yellow, leaving still the mixed solution for 8-30 hours, pouring out the supernatant, washing the obtained turbid solution repeatedly with deionized water, centrifuging to pH value of 5.5-7, and freeze-drying to obtain graphene oxide, where the dosage ratio of phosphorus flake graphite, potassium permanganate, concentrated sulfuric acid and concentrated phosphoric acid is 1 g:(5-10) g:(100-200) ml:(10-20) ml, (b) dispersing commercially available micron boron nitride in 2-10 mol/l sodium hydroxide solution to obtain a 2-10 g/l dispersion solution, placing the obtained dispersion solution in a ultrasonic bath with an oscillation frequency of 26 kHz and an output power of 100-500 W for 2-10 hours, after completing the reaction, naturally cooling to room temperature, washing the product with deionized water until neutral, and placing the product in vacuum oven for drying at 60degrees Celsius for 2-10 hours to obtain boron nitride nanosheet, (c) adding the obtained graphene oxide and boron nitride nanosheet to N,N-dimethylacetamide in a mass ratio of 1:(3-10), performing ultrasonic treatment in ultrasonic bath with an oscillation frequency of 26 kHz and an output power of 100-500 W at room temperature for 2-10 hours to obtain boron nitride graphene oxide filler, where the concentration of graphene oxide is 0.1-0.5 wt.%, (d) adding a diamine monomer to the reaction system obtained in step (c) under the protection of nitrogen atmosphere, adding tetracarboxylic dianhydride within 0.5-1 hour, uniformly stirring at room temperature for 8-16 hours to obtain a mixed solution of boron nitride graphene oxide polyamic acid, where the diamine is p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminophenyl sulfone and/or 4,4'-diaminodiphenylmethane, the tetracarboxylic dianhydride is pyromellitic dianhydride, 4,4'-biphenyltetracarboxylic anhydride and/or 3,3',4,4'-benzophenonetetracarboxylic dianhydride, the molar ratio of diamine and tetracarboxylic dianhydride is 1:1, and the concentration of diamine is 0.1-0.5 mol/l, and (e) casting the obtained mixed solution on a glass plate, baking in oven at 120-180degrees Celsius until the solvent is volatilized completely, placing the mixture in muffle furnace, maintaining the temperature at 280-330degrees Celsius for 1-3 hours, naturally cooling to room temperature, and stripping the sample from glass plate to obtain composite film.