In this study, a series of the PMVS/SiO2/GO-C12-hep (polymethylvinyl siloxane, PMVS) nanocomposites of varying fillers concentration were fabricated employing blending technique. Retained tensile tests showed that tensile strength of PMVS/SiO2/GO-C12-hep nanocomposites improved with increasing of GO-C12-hep content from 0 to 0.5 wt %, but it decreased when the GO-C12-hep content was up to 0.8 wt %. SEM results showed that GO/C12-hep had been dispersed into PMVS matrix, and the interfacial consistency property was very well between GO-C12-hep and PMVS. The degradation mechanism was also analyzed. The thermal stability and the degradation kinetics of nanocomposites had been evaluated using thermo-gravimetric analysis (TGA) at different heating rates in flowing nitrogen. TGA curves revealed that PMVS/SiO2/GO-C12-hep exhibited relatively better thermal stability than PMVS/SiO2, and the degradation temperatures of PMVS/SiO2/GO-C12-hep increased with GO-C12-hep increase. The apparent activation energies (Ea) were estimated with the Flynn-Wall-Ozawa method (FWO method). The Ea of PMVS/SiO2/GO-C12-hep nanocomposites had relevance to their content of GO-C12-hep. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013