▎ 摘　　要

NOVELTY - Preparation of composite material of enhanced nylon 12 grafted with graphene oxide involves: 1) preparing graphene oxide (GO); 2) performing alkalization treatment on coconut shell fiber (CSSP); 3) performing surface modification amination treatment of coconut shell fibers, mass to volume ratio of alkalized coconut shell fibers and deionized water used is 1mg: 0.25-0.55 ml, mass ratio of alkalized coconut shell fibers to sum of N- (3-dimethylaminopropyl) -N '-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide used is 1-3: 1, mass ratio of N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide hydrochloride and N-hydroxysuccinimide used is 1:1; 4) preparing coconut shell fiber surface grafted graphene oxide, mass ratio of graphene oxide and aminated coconut shell fiber used is 0.01-0.1: 1, mass ratio of aminated coconut shell fiber to 4-dimethylaminopyridine used is 1-10: 1; 5) preparing composite material CSSP @ GO-g-PA 12. USE - The method is used for preparing reinforced nylon 12 composite material which has graphene oxide grafted on the surface of MJR3D printed coconut shell fiber. ADVANTAGE - The process enables to increase the roughness of the coconut shell fiber surface grafted graphene oxide, and enhance the transfer effect between matrix and reinforcement in the nylon 12 composite material. The composite material prepared has improved interface performance, mechanical property and biodegradability. DETAILED DESCRIPTION - Preparation of composite material of enhanced nylon 12 grafted with graphene oxide involves: 1) preparing graphene oxide (GO); 2) soaking coconut shell fiber in 5 wt.% sodium hydroxide (NaOH) solution for 6 hours to remove surface impurities, then washing with distilled water until pH is 7, and drying at 60degrees Celsius for 48 hours to form the alkalized coconut shell fiber; 3) adding deionized water into alkalized coconut shell fiber, stirring, titrating with acid to adjust pH to 5-6, adding N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, and activating for 15 minutes to form an activated coconut shell fiber suspension, the mass volume ratio of alkalized coconut shell fibers and deionized water is 1 mg: 0.25-0.55 ml, the mass ratio of alkalized coconut shell fibers to the sum of N- (3-dimethylaminopropyl) -N '-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide is 1-3: 1, the mass ratio of N- (3-dimethylaminopropyl) -N' -ethylcarbodiimide hydrochloride to N-hydroxysuccinimide, is 1:1, adding gamma-mercaptopropyl trimethoxy silane into deionized water, heating to 60degrees Celsius, hydrolyzing for 10 minutes, adding activated coconut shell fiber suspension, stirring for 10 hours, washing with deionized water, drying in vacuum to form aminated coconut shell fibe, the mass ratio of the gamma-mercaptopropyltrimethoxysilane to the activated coconut shell fiber suspension is 1: 1-4; 4) dispersing the graphene oxide in water, performing ultrasonic treatment for 2-3 hours to form a graphene oxide dispersion liquid of concentration 0.1-0.5 mg/ml, then sequentially adding 4-dimethylaminopyridine and aminated coconut shell fiber, reacting for 2 hours under stirring at normal temperature and performing vacuum drying so that graphene oxide is grafted on the surface of the coconut shell fiber, the mass ratio of graphene oxide to aminated coconut shell fiber is 0.01-0.1: 1, the mass ratio of aminated coconut shell fiber to 4-dimethylaminopyridine is 1-10: 1; 5) preparing a mixed solvent by using graphene oxide grafted on coconut shell fiber surface, nylon 12 material particles, hindered phenol, phosphite composite antioxidant, calcium stearate, ethanol, butanone, diethylene glycol and deionized water, placing it in a stainless steel high-temperature reaction kettle and reacting in an oil bath kettle at 170degrees Celsius for 2 hours, after nylon 12 material particles in a reaction system are completely dissolved, violently stirring, cooling with preset speed, sperating CSSP @ GO as a core heterogeneous nucleation of nylon 12 material particles, coating the core heterogeneous nucleation on the surface of the CSSP @ GO, and rapidly cooling to room temperature to form CSSP @ GO-g-PA12 composite powder suspension, carrying out vacuum filtration to recover the solvent, drying and ball milling.