▎ 摘　　要

NOVELTY - Environmentally friendly nanocomposite material comprises e.g. 20-30 pts. wt. polylactic acid, 0.2-0.3 pts. wt. modified nanocellulose, 1-2 pts. wt. nitrogen-doped carbon quantum dot, 7-11 pts. wt. graphene oxide, 0.05-0.1 pts. wt. thiolate-protected nano gold cluster and 0.05-0.1 pts. wt. thiolate-protected nano gold cluster, and the preparation of nanocomposite material, includes preparation of nano cellulose, modifying the nano cellulose, and preparing nitrogen-doped carbon quantum dots and graphene oxide and material compounding. USE - Used as environmentally friendly nanocomposite material. ADVANTAGE - The composite material has excellent mechanical properties, toughness and strength; and is degradable and environmentally friendly. DETAILED DESCRIPTION - Environmentally friendly nanocomposite material comprises 20-30 pts. wt. polylactic acid, 0.2-0.3 pts. wt. modified nanocellulose, 1-2 pts. wt. nitrogen-doped carbon quantum dot, 7-11 pts. wt. graphene oxide, 0.05-0.1 pts. wt. thiolate-protected (Au24 (SC2H4Ph)16) nano gold cluster and 0.05-0.1 pts. wt. thiolate-protected (Au3-6 (SCH(CH3)Ph)24) nano gold cluster, where the preparation of nanocomposite material, includes (i) (a) adding cellulose to an aqueous urea solution for 1 hours, and then repeatedly washing with deionized water to remove urea to obtain wet cellulose, (ii) adding wet cellulose to dilute hydrochloric acid solution, stirring at 45-55 degrees C for 2-3 hours, pouring the reaction solution into a large amount of deionized water, and repeatedly washing to neutral to obtain gelatinous product, and (iii) ball-milling the gel in a ball mill at a speed of 800 revolutions/minute for 3.5 hours to obtain slurry nanocellulose aqueous suspension, (ii) (a) centrifuging the slurry nanocellulose aqueous suspension obtained in the step (i) for 6-9 times with glacial acetic acid, adding concentrated sulfuric acid and adding acetic anhydride to a constant temperature water bath at 45-55 degrees C for reaction and reacting for 1.8-2.3 hours to obtain paste solution, (b) adding 40% acetic acid to the paste solution, stirring continuously, and insulating at 58-60 degrees C for 15-20 minutes, and (c) stirring the accelerate, then adding deionized water, adularescent and loose substances to precipitates, suction filtering the reaction product with vacuum pump, then washing to neutral and vacuum drying to constant weight to obtain modified nanocellulose; (iii) dissolving ammonium citrate in deionized water, stirring until completely dissolved, transferring to a high-pressure hydrothermal kettle equipped with a polytetrafluoroethylene liner, heating at 145-155 degrees C for 6-7 hours, taking out and cooling to room temperature, then dialyzing the obtained solution against a dialysis bag for 20-24 hours and freeze drying the dialysis purified solution to obtain nitrogen-doped carbon quantum dot, (vi) (a) placing three-necked flask in an ice water bath, adding concentrated sulfuric acid and adding graphite powder and sodium nitrate under stirring to controlling the reaction temperature to 6-10 degrees C, (b) adding hydrogen peroxide, stirring the reaction for 25-30 minutes, heating at 33-38 degrees C, stirring for 1-1.5 hours, then adding deionized water, heating at 78-88 degrees C and stirring for 20-25 minutes, and (c) filtering with hot water, the washing with 5% hydrochloric acid solution and deionized water until the pH of the filtrate is 6-7, dispersing under ultrasonic conditions for 1 hour, filtering and drying in a vacuum oven at 60 degrees C to constant weight to obtain graphite oxide, and (v) (a) dissolving polylactic acid in chloroform at room temperature with continuous stirring, then adding modified nanocellulose prepared in step (ii), stirring for 3-4 hours, ultrasonic dispersing for 3-6 minutes, filtering and vacuum drying at 50 degrees C to constant weight to obtain composite base material, and (b) adding composite base material, nitrogen-doped carbon quantum dots, graphene oxide, thiolate-protected (Au24 (SC2H4Ph)16) nano gold cluster and thiolate-protected (Au3-6 (SCH(CH3)Ph)24) nano gold cluster into a twin-screw extruder, blending, extruding and granulating to obtain final product. An INDEPENDENT CLAIM is also included for preparing nanocomposite material, comprising (i) (a) adding cellulose to an aqueous urea solution for 1 hours, and then repeatedly washing with deionized water to remove urea to obtain wet cellulose, (ii) adding wet cellulose to dilute hydrochloric acid solution, stirring at 45-55 degrees C for 2-3 hours, pouring the reaction solution into a large amount of deionized water, and repeatedly washing to neutral to obtain gelatinous product, and (iii) ball-milling the gel in a ball mill at a speed of 800 revolutions/minute for 3.5 hours to obtain slurry nanocellulose aqueous suspension.