A different series of polymer-clay hybrid materials have been prepared by modification of the clay,with different vinyl monomers, followed by polymerization of different ratios of vinyl monomers-clay with the monomers, such as methyl methacrylate, hydroxyethyl methacrylate, and stvrene-maleic anhydride. The materials were investigated by IR, which confirmed the intercalation of vinyl-cation within the clay interlayers, and by TGA, which illustrated that phosphonium cation has high thermal stability than ammonium cation. Swelling studies of these materials in different organic solvents showed that the swelling degree increases as clay ratio decrease, and also showed higher swelling relative to vinyl-clay. X-ray diffraction illustrated that the nanocomposites were exfoliated up to a 25 wt % content of organoclay relative to the amount of polymer. SEM and TEM examined the micrograph, which showed a good dispersion of the polymers into clay galleries, and formation of nanosize particles ranged 150-300 A. (c) 2007 Wiley Periodicals, Inc.