▎ 摘　　要

NOVELTY - Preparing chitosan modified boron nitride and graphene fiber composite material comprises (i) dissolving chitosan in acetic acid solution, adding deionized water and phytic acid solution containing choline chloride, adding boron nitride, performing centrifugation, and drying product to obtain chitosan-modified boron nitride, (ii) preparing graphene fibers by placing natural graphite and sodium nitrate into concentrated sulfuric acid to obtain black solution, dripping potassium permanganate, adding hydrogen peroxide to obtain bright yellow solution, drying filtered product and grinding to obtain graphene oxide, centrifugally washing graphene oxide with hydrochloric acid and distilled water, and drying to obtain graphene fibers, and (iii) adding composite of modified boron nitride and graphene fiber, chitosan-modified boron nitride and graphene fiber into deionized water, obtaining black powder, washing product with concentrated hydrochloric acid and water, and vacuum-drying. USE - The material is useful for thermal conductivity modification of epoxy resin (claimed). ADVANTAGE - The method: utilizes chitosan to modify the boron nitride nano-particles as an interfacial compatibilizer to improve contact interface between the boron nitride and the epoxy resin matrix; improves mechanical properties of epoxy resin matrix, and thermal stability of the epoxy resin matrix and stability of thermal conductivity network, and thermal conductivity of the epoxy resin; utilizes composite heat-conducting material with epoxy resin as matrix in radiating coatings of electronic device; and provides an efficient solution for improving radiating of electronic devices. DETAILED DESCRIPTION - Preparing chitosan modified boron nitride and graphene fiber composite material comprises (i) preparing chitosan-modified boron nitride by dissolving specific amount of chitosan in acetic acid solution, adding specific amount of deionized water and specific amount of phytic acid solution containing choline chloride, then adding specific amount of boron nitride, using cell crusher for ultrasonic treatment, then performing centrifugation for multiple times, taking supernatant respectively, and finally washing with deionized water until product is neutral, and drying product in vacuum environment to obtain chitosan-modified boron nitride, (ii) preparing graphene fibers by placing a specific amount of natural graphite and sodium nitrate into concentrated sulfuric acid to obtain a black solution, stirring in an ice bath for a specific period of time, dripping specific amount of potassium permanganate, continuously stirring in ice bath, dripping specific amount of distilled water to obtain brown solution, diluting brown solution with specific amount of warm water, adding specific amount of hydrogen peroxide to obtain bright yellow solution, filtering bright yellow solution, washing the filtered product with dilute hydrochloric acid and distilled water respectively until the solution is neutral, drying filtered product and grinding to obtain graphene oxide, centrifugally washing graphene oxide with hydrochloric acid and distilled water until neutral respectively, then dispersing graphene oxide in deionized water, injecting solution containing graphene oxide into glass injector, controlling spinning speed by flow pump of spinning needle, rapidly shrinking graphene oxide fiber and curing in high-temperature nitrogen gas flow, reducing obtained the graphene oxide fiber for specific period of time in sodium citrate aqueous solution, repeatedly washing with deionized water until it is neutral, and finally drying in vacuum environment to obtain graphene fibers, and (iii) adding composite of modified boron nitride and graphene fiber, specific amount of chitosan-modified boron nitride obtained in the step (i) and specific amount of graphene fiber obtained in the step (ii) into deionized water respectively, heating and heat-preserving for a specific period of time, quickly cooling in ice bath environment, filtering and drying filtered product in vacuum environment, obtaining black powder, heat preserving under nitrogen atmosphere at high temperature for a specific period of time, washing product with concentrated hydrochloric acid and water for multiple times until neutral, and finally vacuum-drying the product to obtain the finished product. INDEPENDENT CLAIMS are also included for: a chitosan modified boron nitride and graphene fiber composite material prepared by the above-mentioned method; and using the material for thermal conductivity modification of epoxy resin, comprising placing epoxy resin, chitosan modified boron nitride and graphene fiber composite into a planetary vacuum stirrer and mixing for 5 minutes, then taking out material, and pressurizing at 50°C for 2 hours to obtain an epoxy resin material in which chitosan-modified boron nitride and graphene fiber composite material is used as a thermal conductivity filler.