▎ 摘　　要

NOVELTY - The preparation of cellulose nanofiber/graphene oxide composite film involves (1) mixing natural cellulose, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, sodium bromide and deionized water, adding sodium hypochlorite to adjust pH, oxidizing, filtering, washing and drying to obtain cellulose nanofiber, and dispersing in distilled water to obtain cellulose nanofiber dispersion liquid, (2) preparing graphene oxide using Hummers method by placing reaction device in ice water bath, mixing graphite and sodium nitrate, adding concentrated sulfuric acid and potassium permanganate, reacting in water bath, stirring, adding deionized water, increasing reaction temperature, oxidizing, reducing unreacted potassium permanganate with hydrogen peroxide and reacting to form bright yellow solution, filtering, washing, drying, and dispersing in water to obtain graphene oxide dispersion liquid, and (3) mixing with nanofiber dispersion liquid, stirring, processing, casting into film and drying. USE - Preparation method of cellulose nanofiber/graphene oxide composite film. ADVANTAGE - The method enables preparation of cellulose nanofiber/graphene oxide composite film with excellent mechanical property and tensile property, and 10% graphene oxide content. DETAILED DESCRIPTION - The preparation method of cellulose nanofiber/graphene oxide composite film involves (1) adding natural cellulose, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl and sodium bromide to deionized water, stirring, adding sodium hypochlorite to adjust the pH value of the system to 8-12, oxidizing at 0-40 degrees C for 0.5-7 hours, filtering, washing, and drying to obtain cellulose nanofiber, where the moisture content is 75-90%, adding to distilled water, and dispersing to obtain cellulose nanofiber dispersion liquid, (2) preparing graphene oxide by Hummers method, adding deionized water and dispersing to obtain graphene oxide dispersion liquid, where the graphene oxide is specifically prepared using Hummers method by placing a reaction device in an ice water bath, uniformly mixing graphite and sodium nitrate, adding concentrated sulfuric acid and potassium permanganate, reacting for 0.5-2 hours, placing in a water bath, reacting at 30-40 degrees C, stirring for 3-8 hours, adding deionized water to the system to increase the reaction temperature, oxidizing at 85-95 degrees C for 0.5-2 hours, reducing the unreacted potassium permanganate with hydrogen peroxide, and reacting for 0.5-2 hours to form a bright yellow solution, completing the reaction, filtering, washing and drying, and (3) mixing the obtained cellulose nanofiber dispersion liquid with graphene oxide dispersion liquid, stirring the mixed dispersion, ultrasonically processing, casting into a film, and drying.