▎ 摘　　要

NOVELTY - Preparing graphene by a high negative pressure method involves physically exfoliating graphite powder in an instant high negative pressure environment under the protection of nitrogen, carbon dioxide or inert gas. The instantaneous high negative pressure environment refers to an environment where the vacuum degree reaches -0.090 to -0.099 megapascal (MPa) from normal pressure within 0.1-1.0 second. The yield of graphene is greater than 98%, and the number of graphene layers is 1-10. USE - Method for preparing a graphene by a high negative pressure method. ADVANTAGE - The method is simple to operate, effectively reduces production costs, has short process cycle, and suitable for large-scale continuous production. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing a graphene/polyethylene terephthalate (PET)composite material, using the graphene, which involves: adding terephthalic acid, ethylene glycol and sodium acetate to the graphene dispersion; incubating, stirring at 250° C for 1-3 hours, heating to 285° C and vacuumizing, the reaction proceeds until the system no longer exotherms; preparing the graphene/PET composite material by water-cooling and pelletizing; and preparing the graphene dispersion is prepared by dispersing graphene in ethylene glycol and performing ultrasonic dispersion treatment for 30 minutes.