Intercalated modification of Montmorillonite clay (MMT) with three different amino acids-Alanine, Leucine, and Phenylalanine-in the presence of hydrochloric acid followed by surface modification by methyl triethoxy silane coupling agent to produce double modified Montmorillonite clay which is characterized by X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). The data shows an increase in d-spacing of modified clay as a result of cationic exchange. Double modified MMT clay was used in the preparation of Polyacrylate/clay nanocomposites by using an in situ redox emulsion polymerization of polyglycidylmethacrylate (PGMA) and polymethylmethacrylate (PMMA). The structure and properties of the prepared nanocomposites were achieved by XRD, TGA, and SEM. The results show that all weight loses temperatures for the nanocomposite samples are higher than that of pure polymer in both PGMA and PMMA. It is also obvious that the increasing in the clay content plays an effective role in the increasing of thermal stability of these materials. SEM shows that the clay is more homogenously dispersed in PMMA than in PGMA matrix. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1572-1578, 2009