AbstractInorganic nano fillers have demonstrated great potential to enhance the properties of natural rubber (NR). The present article reports the successful development of a NR nanocomposite reinforced with nano silica (SiO2). Its dynamic mechanical properties, thermal aging resistance, and morphology are investigated. The results show that the SiO2 nanoparticles are homogenously distributed throughout the NR matrix in a form of spherical nano‐cluster with an average size of 80 nm when the SiO2 content is 4 wt%. With the introduction of SiO2, the thermal resistance and the storage modulus of NR host significantly increase, and the activation energy of relaxation of the nanocomposite, compared to the raw NR, increases from 90.1 to 125.8 kJ/mol. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers