Polybutadiene-modified clay and its nanocomposites

A butadiene-modified clay was prepared by ionic exchange between sodium montmorillonite and a butadiene surfactant; the butadiene surfactant was obtained from the reaction of vinylbenzyl chloride grafted polybutadiene with a tertiary amine. Nanocomposites of polystyrene, high impact polystyrene, acrylonitrile-butadiene-styrene terpolymer, poly(methyl methacrylate), polypropylene and polyethylene were prepared by melt blending this modified clay with the virgin polymers. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the evaluation of mechanical properties. A morphological study of PBD-modified clay-polymer nanocomposites shows that all the composites are immiscible micro-composites. The consistency of the result from XRD and TEM with that of cone calorimetry indicates that the cone calorimeter must also be considered as another method to examine the bulk sample and infer if good dispersion of the clay in the polymer has been achieved. The mechanical properties of the nanocomposites prepared from different methods show that the mechanical properties are, in general, predictable based on the type of dispersion. (C) 2004 Elsevier Ltd. All rights reserved.