Based on the results of bound-rubber determination, Monsanto rheometric studies, solvent swelling, measurement of physical properties, and infrared spectroscopic studies, it is revealed that epoxidized natural rubber (ENR) and hard clay interact chemically to form Si-O-C bond during high-temperature (180 degrees C) molding. It is also observed that addition of the silane coupling agent N-3-(N-vinyl benzyl amino)ethyl-gamma-amino propyl trimethoxy silane monohydrogen chloride enhances the extent of the chemical interaction with the formation of coupling bonds of Si-O-Si type between clay and the coupling agent and C-N bonds between ENR and the coupling agent.