In this investigation, graphene 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 ) 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. © 2012 Elsevier B.V. All rights reserved.