Preparation and characterization of polystyrene-clay nanocomposites by free-radical polymerization

The polymerizable cationic surfactant, vinylbenzyldimethylethanolammouium chloride (VBDEAC), was synthesized to functionalize montmorillonite (MMT) clay and used to prepare exfoliated polystyrene-clay nanocomposites. The organophilic MMT was prepared by Na+ exchanged montmorillonite and ammonium cations of the VBDEAC in an aqueous medium. Polystyrene-clay nanocomposites were prepared by free-radical polymerization of the styrene containing intercalated organophilic MMT. Dispersion of the intercalated montmorillonite in the polystyrene matrix determined by X-ray diffraction reveals that the basal spacing is higher than 17.6 nm. These nanocomposites were characterized by differential scanning calorimetry (DSC), transmission electron micrograph (TEM), thermal gravimetric analysis (TGA), and mechanical properties. The exfoliated nanocomposites have higher thermal stability and better mechanical properties than the pure polystyrene. (C) 2002 Wiley Periodicals, Inc.