▎ 摘　　要

Exfoliation and preparation of large interlayer spacing and reactive graphene oxide (GO) powder are of crucial importance and neck technologies for their applications in polymer composites. Herein, we reported an innovative approach to prepare a large interlayer spacing reactive NCO-GO powder by covalent functionalization of GO with 4,4'-diphenylmethane diisocyanate (MDI). The morphology, microstructure, interlayer spacing, dispersion, and thermal stability of the NCO-GO powder were seriously investigated by FT-IR, XPS, XRD, TEM, TG, and Raman. Interlayer spacing of NCO-GO nanosheets was successfully expanded from 0.83 nm to 2.43 nm after modification, the NCO-GO powder showed better dispersion stability than GO in polar solvents and higher decomposition temperature. The fabricated novel NCO-GO powder showed a great prospect in the future to prepare graphene-based PU composites with significantly enhanced electrical conductivity and mechanical properties of PU elastomer.