▎ 摘　　要

NOVELTY - The preparation of polymethyl methacrylate composite material, involves (1) mixing expanded graphite, concentrated sulfuric acid and oxidizing agent to obtain oxidized expanded graphite, (2) adding deionized water to oxidized graphite, adding surface active agent to obtain graphene aqueous solution, (3) centrifugal removing of upper liquid layer, dispersing graphene to N-methyl pyrrolidone (NMP) to obtain graphene solution, adding mixed liquid of methyl methacrylate and benzoyl peroxide to graphene solution, increasing temperature, reacting, removing solvent, washing, and drying. USE - Preparation of low oxidation degree graphene modified polymethyl methacrylate composite material used in vehicle. ADVANTAGE - The method enables preparation of graphene modified polymethyl methacrylate composite material whose glass transition temperature is increased to 9 degrees C than pure polymethyl methacrylate, increases elastic energy storage modulus to 43.7%, increases heat loss temperature to 87 degrees C, conductivity of composite material is 50% S/m, and the modified polymethyl methacrylate composite material has excellent mechanical and electrical performances. DETAILED DESCRIPTION - The preparation of graphene modified polymethyl methacrylate composite material, involves (1) mixing 1-3 pts. wt. expanded graphite, 50-600 pts. wt. concentrated sulfuric acid and 1-5 pts. wt. oxidizing agent to obtain oxidized expanded graphite, (2) adding 50-600 pts. wt. deionized water to oxidized expanded graphite, adding 0.01-10 pts. wt. surface active agent to obtain graphene aqueous solution, (3) centrifugal removing of upper liquid layer, dispersing graphene to NMP to obtain graphene solution, adding mixed liquid of methyl methacrylate and benzoyl peroxide to graphene solution, increasing temperature to 70-90 degrees C, reacting for 1-24 hours, removing solvent through centrifugation, washing, vacuum drying, to obtain graphene modified polymethyl methacrylate composite material comprising methyl methacrylate and dibenzoyl peroxide in mass ratio of (50-500):1.