▎ 摘　　要

NOVELTY - Preparation of graphene-modified polymethyl methacrylate composite material with super high conductivity includes taking expanded graphite, adding concentrated sulfuric acid and oxidizing agent, slightly oxidizing, obtaining slightly oxidized expanded graphite (EGIC), adding deionized water and ethanol, uniformly stirring, obtaining EGIC mixed solution, taking silane coupling agent, adding water, stirring, obtaining silane coupling agent solution, hydrolyzing, mixing with EGIC mixed solution, continuously reacting, obtaining product, washing with methanol and water and suction filtering. USE - Preparation of graphene-modified polymethyl methacrylate composite material (claimed). ADVANTAGE - The method provides graphene-modified polymethyl methacrylate composite material with super high conductivity. When mEGIC content reaches 10 wt.%, the graphene-modified polymethyl methacrylate composite material has increased glass transition temperature by 18 degrees C, increased elastic energy storage modulus by 300%, and conductivity of more than 1700 S/m, compared with pure polymethyl methacrylate. DETAILED DESCRIPTION - Preparation of graphene-modified polymethyl methacrylate composite material with super high conductivity comprises taking 1-3 g expanded graphite, adding 200-600 ml concentrated sulfuric acid and oxidizing agent, slightly oxidizing, obtaining EGIC, adding 50-150 ml deionized water and 100-300 ml ethanol, uniformly stirring at 60-70 degrees C, obtaining EGIC mixed solution, taking 2.5-7.5 ml silane coupling agent, adding 40-120 ml water, stirring, obtaining silane coupling agent solution, hydrolyzing at pH 4-5, mixing with EGIC mixed solution, continuously reacting at 60-70 degrees C for 2 hours, obtaining product, washing with methanol and water, suction filtering, obtaining siloxane-modified expanded graphite (mEGIC), adding mEGIC, methyl methacrylate (MMA) and dibenzoyl peroxide (BPO) in N-methylpyrrolidone solvent, stirring at room temperature, raising temperature to 70-90 degrees C, reacting for 7-12 hours, washing product with methanol, centrifuging and vacuum drying to obtain graphene-modified polymethyl methacrylate composite material, where mEGIC is at 1-10 mass% based on the mass of graphene-modified polymethyl methacrylate composite material. The mass ratio of MMA and BPO is 100-300:1.