Abstract: | Halogen‐containing organically modified clay nanocomposites have been prepared and it was found that the presence of bromine enhances the fire retardancy of polystyrene and polypropylene nanocomposites, compared with the virgin polymers. The nanocomposites were evaluated by X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and cone calorimetric measurements. The UL‐94 test gave a V‐0 rating for some samples while cone calorimetry gave a reduced PHRR. Both the amount and identity of the bromine‐containing compound and the mode of preparation, which controls the dispersion, have a significant effect on the results. Bromine‐containing materials, at very low loading, approximately 6% or less bromine, give excellent results when the clay loading was about 3%. Copyright © 2005 John Wiley & Sons, Ltd. |