Zhang J, Zhang HP (2005) Study on the flammability of HIPS-montmorillonite nanocomposites prepared by static melt intercalation. Journal of Fire Sciences 23(3), 193-208. [In English]

Web link:http://dx.doi.org/10.1177/0734904105046278

Keywords:

HIPS, nanocomposite, montmorillonite, flame retardant, static melt, intercalation, cone calorimeter,

Abstract: The HIPS-montmorillonite nanocomposites are prepared by the static melt intercalation method. XRD analysis indicates that the spacing of the silicate layers increased from 1.51 nm for the untreated montmorillonite to 3.44 nm for the HIPS-montmorillonite prepared by the melt intercalation method. The cone calorimeter test results show that the addition of organically modified montmorillonite (OMMT) significantly reduces the heat release rates and mass loss rates of the high-impact polystyrene (HIPS). Compared with the pure HIPS, the heat release rates of the HIPS-OMMT composites are reduced by 29.5% at 3 phr, 44.8% at 5 phr, 52.1% at 10 phr, and 61.4% at 20 phr levels. The char residues of the composites are examined by the scanning electron microscope (SEM) technique. The fine surface morphology obtained for the residues shows that distinctly separated layers are present in the HIPS-OMMT composites while the original silicate layers remain untouched in the HIPS-untreated montmorillonite mixtures. It is shown that the intercalated composite improves the flame retardancy of HIPS polymer in terms of heat release rates. The analysis based on the morphology of char residue indicates that those separated layers, due to the intercalation, construct a network-like structure and thereby function as a large shield and barrier to protect effectively from heat transfer and volatile evaporation, resulting in the reduction of flammability.