The nanocomposites were prepared using various fluoroelastomers and nanoclays by a solution mixing process. The properties of the nanocomposites, prepared by this method in MEK, were found to be a function of rubber solution concentration. Optimum properties were achieved at 20 wt% solution. Characterization of all the nanocomposites was done by using XRD and AFM. Exfoliation was observed with both the unmodified and the modified clays at low loading in all the fluoroelastomers at unvulcanized condition. The mechanical and dynamic mechanical properties were studied. Best properties were observed with the unmodified clay at 4 phr loading. At higher filler loading, the properties deteriorated. The results were explained with the help of thermodynamics, soft-hard acid base theory and surface energies. Diffusion and sorption of methyl ethyl ketone and tetrahydrofuran through fluoroelastomer-clay nanocomposites were also investigated. Best solvent resistance was observed in the case of the unmodified clay filled sample. From the permeation data, for the first time, aspect ratio of nanoclays in different composites was calculated and found to have good correlation with the morphology data obtained from transmission electron microscopy. Dynamic mechanical thermal analysis was performed on the nanocomposites over a range of temperatures (-60 to +60°C), frequencies (0.032 to 32 Hz) and strains (0.002 to 2%). There were significant changes in the glass transition temperature and storage modulus with the addition of small amount (4 phr) of the nanofillers. Low and high temperature degradation of neat fluoroelastomer and its nanocomposites was carried out. Unlike other properties, thermal stability increases with increasing filler loading. Montmorillonite clay was synthesized in the laboratory with an intention to understand the structure-property relationship of polymer nanocomposites, with special reference to the characteristics of the nanoclays. Mechanical, dynamic mechanical, swelling and thermal properties of these synthetic clay- fluoroelastomer nanocomposites are better than the natural clay filled samples.