▎ 摘　　要

NOVELTY - Modified three-dimensional graphene is connected with modifying group provided bymodifying agent, modifying agent is aromatic diamine compound. USE - Modified three-dimensional graphene. ADVANTAGE - The modified three-dimensional graphene has high shape stability, the obtained polymer composite material has excellent mechanical properties, and can obtain high electrical conductivity at a low graphene content. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing modified three-dimensional graphene, which involves mixing modifier with thegraphene oxide solution, then introducing the reducing agent and adjusting the pH to alkalinereaction system to obtain alkaline solution, where modifying agent is aromatic diamine compound, heating solution to produce graphene hydrogel, removing the unreacted modifier in the graphene hydrogel, and performing freeze-drying treatment, obtaining modified three-dimensional graphene; (2) a polymeric composite material, which comprises 0.1 to 2 vol.% three-dimensional graphene, preferably from 0.2 to 1 vol.%, more preferably from 0.3 to 0.5 vol.%, where polymer is one or more of a polyurethane, a polyether amine, and an epoxy resin; and (3) a method for preparing polymeric composite material, which involves immersing the modified three-dimensional graphene in a polymer, followed by heat curing to obtain a polymerized composite material, where the polymer being a thermosetting polymer, and modified three-dimensional graphene has pores filled with a cured polymer.