A novel organomodified montmorillonite prepared by solid-state method and its nanocomposites with natural rubber were studied. The nanocomposites were prepared by traditional rubber mixing and vulcanizing process. The properties of solid-state organomodified montmorillonite were investigated by Fourier-transform infrared spectroscopy (FITR) and thermogravimetric analysis (TGA). The dispersion of the layered silicate in rubber matrix was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the nanocomposites consisting of solid-state organomodified montmorillonite and natural rubber are obtained. The solid-state organomodified montmorillonite can not only accelerate the curing process, but also improve the mechanical and aging resistance properties of NR. The properties improvement caused by the fillers are attributed to partial intercalation of the organophilic clay by NR macromolecules. In addition, the dynamic mechanical analysis (DMA) results showed a decrease of tan delta max and increase of T-g when the organoclay is added to the rubber matrix, which is due to the confinement of the macromolecular segments into the organoclay nanolayers and the strong interaction between the filler and rubber matrix. (c) 2007 Wiley Periodicals, Inc.