▎ 摘　　要

NOVELTY - Preparing modified graphene oxide comprises (i) taking 1-20 g methyl methacrylate, 0.1-5 g dibromoisobutyl acetate, 50-100 mg triphenylphosphine, 40-80 mg ascorbic acid, 30-100 mg ferric chloride and 5-50 g N,N-dimethylformamide per gram of graphene oxide, the graphene oxide, mixing and ultrasonically dispersing graphene oxide and N,N-dimethylformamide to obtain an ultrasonic dispersion; (ii) adding ferric chloride, triphenylphosphine, ethyl dibromoisobutyrate and ascorbic acid to the ultrasonic dispersion to obtain a raw material mixture in a nitrogen atmosphere, reacting at 80?OC to obtain a reaction product; and (iii) removing the self-polymerization product in the reaction product, filtering and vacuum drying. USE - The polylactic acid-modified graphene oxide nano-composite is useful in medical materials, food packaging materials, agricultural film materials or fiber materials (claimed). ADVANTAGE - The method has significant improvement in mechanical properties and heat resistance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) modified graphene oxide prepared as mentioned above; (2) polylactic acid-modified graphene oxide nano-composite, prepared by (a1) mixing the required amount of lactic acid or L-lactide or D-lactide or D,L-lactide or meso-lactide, zinc lactate, hexamethylene diisocyanate and modified graphene oxide raw materials under the protection of nitrogen, increasing the temperature of the mixed raw materials at 120-180 degrees C and reacting at 120-180 degrees C for 0.5-3 hours to obtain a reaction product 1, (a2) cooling the reaction product to room temperature, adding ethyl acetate to dissolve, adding distilled water, forming and separating the precipitate, (a3) adding ethyl acetate to the precipitate obtained in the second step to dissolve, repeat the second step 2-3 times, and (a4) vacuum drying the precipitate; and (3) preparing polylactic acid-modified graphene oxide nano-composite, comprising (b1) mixing lactic acid or L-lactide or D-lactide or D,L-lactide or meso-lactide, zinc lactate, hexamethylene diisocyanate and modified graphene oxide to obtain a mixed raw material under the protection of nitrogen, increasing the temperature of the mixed raw material at 120-180 degrees C, reacting at a temperature of 120-180 degrees C for 0.5-3 hours to obtain a reaction product 1, and (b2) cooling the reaction product to room temperature as soon as possible, adding ethyl acetate to dissolve and distilled water forming and separating precipitate, adding ethyl acetate to the precipitate obtained and repeating the step 2 to 3 times and vacuum drying.