▎ 摘　　要

NOVELTY - Preparation of sand core coating involves mixing cyclodextrin, ethylenediamine, 2-fluorenbutyric acid, N-hydroxysuccinimide, dimethylaminopyridine and N,N-dimethylformamide, putting into reactor, adding dicyclohexylcarbodiimide, stirring, putting into acetone to precipitate, centrifuging to obtain mixture (A), immersing graphene nanosheets in nitric acid solution, ultrasonically processing, filtering, rinsing with deionized water, drying, putting into reaction kettle, adding acylating agent, filtering, rinsing, drying, putting into reaction kettle, adding catalyst, glycidyl methacrylate and mixture (A), maintaining reactor in nitrogen environment, maintaining temperature at 100-120 degrees C, reacting for 20-25 hours, performing suction filtration, washing, drying to obtain material (B), putting silicon fine powder, material (B), suspending agent, epoxy resin, silica sol and deionized water into high-speed stirring tank and taking them out after 2-2.5 hours of high-speed stirring treatment. USE - Preparation of sand core coating for improving casting quality. ADVANTAGE - The preparation method is simple, economical, safe and environmentally-friendly and provides coating with improved strength, impact resistance and thermal conductivity. The coating does not crack easily and effectively improve the surface accuracy and quality of casting. DETAILED DESCRIPTION - Preparation of sand core coating for improving casting quality, involves mixing cyclodextrin, ethylenediamine, 2-fluorenbutyric acid, N-hydroxysuccinimide, dimethylaminopyridine and N,N-dimethylformamide in a weight-volume ratio of (20-25) g:(70-90) mL:(5-7) g:(2-3) g:(1-1.5) g:(360-380) mL, feeding the obtained mixture into a reactor, adding dicyclohexylcarbodiimide to reaction kettle, stirring for 3-5 hours, adding acetone to obtained precipitate, centrifuging, removing supernatant to obtain mixture (A), immersing graphene nanosheets in nitric acid solution, ultrasonically processing for 2-3 hours, filtering, rinsing with deionized water to neutrality, drying, placing the processed graphene nanosheets into reaction kettle, adding acylating agent, filtering after ultrasonic treatment for 20-25 minutes, rinsing with deionized water to neutrality, drying, putting processed graphene nanosheets into reaction kettle, adding catalyst, ligand, organic solvent, glycidyl methacrylate and mixture (A), maintaining reactor in nitrogen environment, maintaining temperature at 100-120 degrees C, reacting for 20-25 hours, performing suction filtration, washing with deionized water, drying to obtain material (B), putting 40-45 pts. wt. silicon fine powder, 8-10 pts. wt. talc, 6-8 pts. wt. material (B), 1-2 pts. wt. suspending agent, 3-5 pts. wt. epoxy resin, 1-3 pts. wt. silica sol and 70-75 pts. wt. deionized water into high-speed stirring tank and separating the obtained product after 2-2.5 hours of high-speed stirring treatment.