In this investigation, graphe oxide nanosheets (GONs) were made from expandable graphite after thermal shock in air and supersonic bath. SEM (scanning electron microscope), TEM (transmission electron microscope) and XRD (X-ray diffraction) were used to characterize the structure of GONs, and then were functionalized using a coupling agent, 3-aminopropyltriethoxsilane (APTS), to produce covalent bonds between the organic and inorganic phases, enhancing the thermal stability of the composites. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS) were adopted to characterize the functionalization reaction between APTS and GNOs. It is affirmed that APTS has reacted with GONs. The functionalized GONs (FGONs) had -OEt functional groups that reacted with silane modified methyl methacrylate through the sol-gel reaction. The results of thermogravimetric analysis (TGA), integral procedure decomposition temperature (IPDT) and thermogravimetric difference (TG(Delta)) reveal that FGONs can improve the thermal stability of composites. The four-point probe was used to measure the surface resistivity of composites. The results showed the PMMA/FGONs composites which contained low concentration of additives possess excellent electrical property. This kind of composites can be used in antistatic application to prevent fire accident happen. (C) 2012 Elsevier B.V. All rights reserved.