▎ 摘　　要

NOVELTY - Preparation of graphene/polyimide composite film involves placing graphene oxide/polyamic acid composite film in hot-pressing sintering furnace, imidizing, carbonizing at 700-1000 degrees C for 1 hour, obtaining carbonized film, adding carbonized film into graphitization furnace, graphitizing at 2000-2800 degrees C under protection of argon atmosphere at the rate of 20 degrees C/minutes for 30-60 minutes, naturally cooling to room temperature, obtaining crude graphene/polyimide composite film, and pressing resultant film with pressure of 30 MPa for 1-30 minutes by tabletting machine. USE - Preparation of graphene/polyimide composite film used for portable wearable electronic device (claimed). ADVANTAGE - The method efficiently provides graphene/polyimide composite film having thickness of 3-8 mu m, thermal conductivity of 1176.46-1545.57 Wx m-1, and excellent flexibility and heat-conducting property. DETAILED DESCRIPTION - Preparation of graphene/polyimide composite film involves respectively dissolving 4,4'-diaminodiphenyl ether and pyromellitic dianhydride in N,N-dimethylformamide, obtaining 4,4'-diaminodiphenyl ether solution and pyromellitic dianhydride solution, adding graphene oxide powder to 4,4'-diaminodiphenyl ether solution and pyromellitic dianhydride solution, at power of 300 W and frequency of 40 kHz, uniformly dispersing graphene oxide in 4,4'-oxydianiline solution and pyromellitic dianhydride solution, obtaining graphene oxide/pyromellitic dianhydride mixed solution and graphene oxide/4,4'-diaminodiphenyl ether solution, adding graphene oxide/pyromellitic dianhydride mixed solution to graphene oxide/4,4'-diaminodiphenyl ether solution, heating at 30-60 degrees C under nitrogen atmosphere, controlling mixing speed of 200 rpm for 1-4 hours, obtaining graphene oxide/polyamic acid mixed solution, transferring resultant mixed solution to evaporating dish to carry out self-assembly at gas-liquid interface, obtaining graphene oxide/polyamic acid composite film, placing graphene oxide/polyamic acid composite film in a hot-pressing sintering furnace, controlling pressure at 15 MPa at the heating rate of 1-5 degrees C/minute, imidizing at 170-350 degrees C for 1-4 hours at the rate of 5-10 degrees C/minute, carbonizing at 700-1000 degrees C for 1 hour, obtaining carbonized film, adding carbonized film into graphitization furnace, graphitizing at 2000-2800 degrees C under protection of argon atmosphere at the rate of 20 degrees C/minutes for 30-60 minutes, naturally cooling to room temperature, obtaining crude graphene/polyimide composite film, and pressing resultant film with pressure of 30 MPa for 1-30 minutes by tabletting machine.