Spontaneous formation of an exfoliated polystyrene-clay nanocomposite using a star-shaped polymer.

Mixtures of five-arm star polystyrene with an organoclay spontaneously formed exfoliated nanocomposites when annealed, validating a recent theoretical prediction by Singh and Balazs (Polym. Int. 2000, 49, 469.). An analogous linear polystyrene sample produced only an intercalated morphology under the same conditions. The nanocomposite morphologies were characterized by X-ray diffraction and transmission electron microscopy. These results suggest a general strategy for forming exfoliated nanocomposites in commodity polymers via melt compounding.