Functionalization of montmorillonite clay has been done using 3-aminopropyltriethoxysilane in the presence of various solvent media. Qualitative evidence of the presence of ammosilane attached to the clay platelets have been identified using Fourier transform infrared spectroscopy (FTIR) and Si-29 and C-13 solid-state nuclear magnetic resonance (NMR) spectroscopy. Grafting yield has been calculated using thermogravimetric analysis and total grafting yield increases with the solvent surface energy. X-ray diffraction studies of the silane functionalized montmorillonite clay exhibits two peaks, which may be attributed to intercalation and surface interaction with the broken edge platelets. Functionalized clay has been characterized by surface area measurements to understand the influence of solvents on the surface area of the functionalized clay. (c) 2006 Published by Elsevier Inc.