A study of morphology and intercalation kinetics of polystyrene-organoclay nanocomposites

Temperature-modulated differential scanning calorimetry (TMDSC) is used to study the heat capacity (C-p) of monodisperse polystyrene in the nanocomposites. It is found that the bulk portion of polystyrene in the nanocomposites has a similar temperature range of glass transition behavior as pure polystyrene, while the normalized Delta C-p of polystyrene in the nanocomposites strongly depends on the polystyrene concentration. Results from TMDSC, especially the combination of kinetic study of TMDSC and X-ray diffraction, indicate that intercalated polystyrene does not contribute to the Delta C-p and does not have glass transition at the regular glass transition temperature. The maximum amount of intercalated polystyrene is around 40 wt %, and this amount will not increase as polystyrene concentration increases as long as the polystyrene with the same molecular weight is used. On the other hand, the amount of intercalated polystyrene increases when polystyrene molecular weight decreases.