Preparation of polystyrene-clay nanocomposites via dispersion polymerization using oligomeric styrene-montmorillonite as stabilizer
This study describes the preparation of polystyrene-clay nanocomposite (PS-nanocomposite) colloidal particles via free-radical polymerization in dispersion. Montmorillonite clay (MMT) was pre-modified using different concentrations of cationic styrene oligomeric ('PS-cationic'), and the subsequent modified PS-MMT was used as stabilizer in the dispersion polymerization of styrene. The main objective of this study was to use the clay platelets as fillers to improve the thermal and mechanical properties of the final PS-nanocomposites and as steric stabilizers in dispersion polymerization after modification with PS-cationic. The correlation between the degree of clay modification and the morphology of the colloidal PS particles was investigated. The clay platelets were found to be encapsulated inside PS latex only when the clay surface was rendered highly hydrophobic, and stable polymer latex was obtained. The morphology of PS-nanocomposite material (after film formation) was found to range from partially exfoliated to intercalated structure depending on the percentage of PS-MMT loading. The impact of the modified clay loading on the monomer conversion, the polymer molecular weight, the thermal stability and the thermomechanical properties of the final PS-nanocomposites was determined. © 2012 Society of Chemical Industry.