▎ 摘　　要

To improve the dispersion and compatibility of thick-sheet graphene (TSG) in the polymer, herein, ionic liquid modified multilayer graphene (MG-IL) is fabricated. Under the mechanically stripping, the ionic liquids are uniformly distributing on the surface of graphene sheet to realize the functionalization of TSG. Through adjusting the content of IL, MG-2IL sample has thin lamellae, rough surface, and a good hydrophilicity. When filled into high heat resistant polyethylene (PERT), the MG-2IL/PERT composite presents a higher thermal conductivity and enhanced mechanical properties than that of TSG/PERT. When the MG-2IL fraction is 1%, the tensile strength, bending modulus and impact strength of MG-2IL/PERT composite is 18.39 MPa, 308.65 MPa and 85.24 kJ/m(2), which is 16.3%, 3.3%, and 8.0% higher than that of TSG/PERT composite, respectively. The thermal conductivity increases to 0.492 W center dot m(-1)center dot k(-1), about 61.3% higher than that of pure PERT and 11.1% higher than that of TSG/PERT composite. The MG-2IL/PERT composite also shows the fastest heat dissipation rate. Considering the high thermal conductivity and mechanical performance, the MG-2IL displays a promising application potential for fabricating the composites with high thermal conductivity.