▎ 摘　　要

NOVELTY - Preparing the graphene modified polymer composite material comprises comprising e.g. preparing the natural crystalline flake graphite by Hummers method to form graphene oxide, dispersing the graphene oxide in the aqueous solution, and performing ultrasonic treatment to obtain the graphene oxide dispersion liquid, taking obtained graphene oxide dispersion liquid and adjusting pH, adding silane coupling agent into the graphene oxide dispersion liquid to stir and hydrolyze, then placing the reactant after stirring into constant temperature water bath for magnetic stirring, placing the reactant after magnetic stirring into oil bath, adding 0 hydrazine hydrate for reflux reaction, and cooling to room temperature and taking out the reactant, adding acetone in the reactant to wash the unreacted silane coupling agent, then vacuumizing and filtering and adjusting the pH of the reaction liquid to neutral, performing vacuum drying treatment to obtain modified graphene. USE - The method is useful for preparing the graphene modified polymer composite material. ADVANTAGE - The method prepares graphene oxide by the Hummers method, and then the graphene oxide is grafted and modified by the silane coupling agent containing the matrix group and reduced to obtain the modified graphene; improves graphene in the organic dispersibility in the solvent, reduces graphene oxide to graphene; adds filler, which can exert its inherent performance advantages, and enhances the thermal and mechanical properties of the composite material, when the filler is added in a small amount, improves the thermal conductivity, thermal stability and tensile strength of the composite material, and improve its comprehensive performance. DETAILED DESCRIPTION - Preparing the graphene modified polymer composite material comprises comprising (i) preparing the natural crystalline flake graphite by Hummers method to form graphene oxide; (ii) dispersing the graphene oxide obtained in the step one in the aqueous solution, the dispersion concentration is 1.9-2.1 mg/ml, and performing ultrasonic treatment to obtain the graphene oxide dispersion liquid, the ultrasonic treatment time is 2-2.5 hours; (iii) taking 50 ml obtained graphene oxide dispersion liquid and adjusting pH, when the pH value of the graphene oxide dispersion liquid is 3-4, adding 190-210 mg silane coupling agent into the graphene oxide dispersion liquid to stir and hydrolyze for 2-2.5 hours, then placing the reactant after stirring into constant temperature water bath for magnetic stirring at 60-65 degrees C for 5-7 hours; (iv) placing the reactant after magnetic stirring in the step (iii) into 90-100 degrees C of oil bath, adding 0.5-0.6 ml hydrazine hydrate for reflux reaction, and cooling to room temperature and taking out the reactant, where the reflux reaction time is 12-13 hours; (v) adding acetone in the reactant obtained in step (iv) to wash the unreacted silane coupling agent, then vacuumizing and filtering and adjusting the pH of the reaction liquid to neutral, performing vacuum drying treatment to the reaction liquid with neutral pH to obtain modified graphene, the vacuum drying temperature is 50-60 degrees C; (vi) dispersing the modified graphene obtained in step (v) in 30-35 ml n-methyl-2-pyrrolidone (NMP), cutting and stirring for 30-35 minutes, then performing ultrasonic treatment to obtain modified graphene dispersion liquid; the time of ultrasonic treatment is 2-2.5 hours; (vii) gradually adding the modified graphene dispersion obtained by the step (vi) to 30-35 ml NMP dissolved with polyvinylidene fluoride, and continuously stirring, the adding amount of the polyvinylidene fluoride is 5-7 g; (viii) mechanically stirring the mixed solution obtained in step (vii) at constant temperature for 6-6.5 hours to form uniform casting film liquid, then filtering the casting film liquid, and the casting film liquid after filtering is subjected to vacuum ultrasonic de-foaming treatment, the time of de-foaming treatment is 2-2.5 hours, and then allowing to stand for 1-1.5 hours after deaeration treatment; and (ix) pouring the casting solution obtained in step (viii) in a clean, horizontal mold, and placing in the constant temperature oven of 100-120 degrees C until the solvent is volatilized completely.