NEW HYBRID NANOCOMPOSITES BASED ON AN ORGANOPHILIC CLAY AND POLY(STYRENE-B-BUTADIENE) COPOLYMERS

The preparation, by direct melt intercalation, and the properties of n ew hybrid organic-inorganic nanocomposites, consisting of a commercial sample of poly(styrene-b-butadiene) copolymer (SBS) and a commercial organophilic clay containing the dioctadecyl dimethyl ammonium salt ar e described. In addition, several mixtures between the same copolymer and an unfunctionalized clay were prepared and studied. XRD spectra sh owed a partial insertion of the SBS block copolymer segments in the in terlayers of the organophilic clay, accompanied by a loss of correlati on within the layers. The degree of insertion increased by annealing t he nanocomposites at 120 degrees C for increasing time periods. No int eraction between the polymer matrix and the unfunctionalized clay was found. The storage modulus value, in the plateau region between the gl ass transition processes of the polybutadiene and the polystyrene bloc ks, and the glass transition temperature of the polystyrene block doma in increase as both the organophilic clay content and the annealing ti me increase. The glass transition process of the polybutadiene block d omain is practically unaffected by the filler content and the annealin g treatments, These data are most promising for upgrading the thermo-m echanical behavior and the application temperature window of the SBS t hermoplastic elastomers through the preparation of nanocomposites empl oying suitably designed organophilic clays.