▎ 摘　　要

NOVELTY - Preparation of graphene flame-retardant coating material involves adding graphene nanosheets and dicyclohexylcarbodiimide to 3-aminopropyltriethoxysilane, reacting at 20-100 degrees C, adding resultant organosilane-modified functionalized graphene nanosheets to acetone, dispersing, adding epoxy resin and low-molecular weight polyamide, stirring, obtaining functionalized graphene nanosheet/epoxy resin nanocomposite, mixing nanocomposite with water and curing agent, adding dispersant and defoaming agent, mechanically-stirring and dispersing. USE - Preparation of graphene flame-retardant coating material (claimed). ADVANTAGE - The method enables efficient preparation of graphene flame-retardant coating material. The surface modified organosilane can avoid re-stacking and aggregation of the graphene sheets, such that the thermal stability and tensile strength of the graphene flame-retardant coating material are improved. The integrated functional material can increase the oxygen index and tensile strength of the epoxy resin, and reduce heat release rate peak and total heat release amount. The coating material can catalyze the degradation of epoxy resin to form a dense and porous carbon layer covered on a surface of the polymer, thus preventing heat and mass exchange between the gas phase and the solid phase, and delaying the further degradation of internal material. DETAILED DESCRIPTION - Preparation of graphene flame-retardant coating material involves adding 50-100 mg graphene nanosheets and 10-50 mg dicyclohexylcarbodiimide to 10-50 ml 3-aminopropyltriethoxysilane, dispersing at room temperature for 0.5-3 hours, reacting at 20-100 degrees C for 3-15 hours, cooling, centrifuging, washing the resultant product, vacuum drying, obtaining organosilane-modified functionalized graphene nanosheets, adding 50-100 mg organosilane-modified functionalized graphene nanosheets to acetone, ultrasonically-dispersing until the formation of uniform black dispersion, adding 5-10 g epoxy resin, mixing uniformly, placing the resultant mixture in a vacuum oven to remove the solvent, adding 1-10 g low-molecular weight polyamide, stirring at 20-100 degrees C for 1-5 hours, obtaining functionalized graphene nanosheet/epoxy resin nanocomposite, mixing 50-100 pts. wt. functionalized graphene nanosheet/epoxy resin nanocomposite, 50-100 pts. wt. water and 100-200 pts. wt. curing agent, adding 2-5 pts. wt. dispersant and 1-3 pts. wt. defoaming agent, mechanically-stirring and dispersing for 0.5-1 hour. The graphene nanosheets are prepared by mixing 0.5-3 g 325 mesh-graphite and 1-3 g sodium nitrate under ice bath, adding 20-50 ml sulfuric acid, stirring at 350 rpm for 30-60 minutes, adding 2-5 g potassium permanganate, slowly adding the resultant mixture into a three-necked flask, stirring for 2-4 hours, removing the ice bath, heating at 30-50 degrees C for 30-60 minutes, adding 150-300 ml deionized water, heating at 98 degrees C for 15-30 minutes, adding 100-200 ml deionized water, stirring, heating, adding hydrogen peroxide until disappearance of oxygen bubbles, layering, removing supernatant, washing the lower layer solution with distilled water to neutral, formulating the resultant solution into 1-3 mg/ml oxidized graphene neutral solution, adding 1-6 ml hydrazine hydrate, adjusting pH of the solution to 8-10 using sodium carbonate, heating at 80 degrees C for 1-3 hours, precipitating, filtering, repeatedly washing the resultant precipitate with ethanol and distilled water and vacuum drying at 60-80 degrees C for 12-24 hours.