Synergistic Study of Carbon Nanotubes, Rice Husk Ash and Flame Retardant Materials on the Flammability of Polystyrene Nanocomposites

The inclusion of various nanomaterials in polymeric materials reduces their flammability and enhances their thermal stability. In this study new composites of polystyrene and diammonium hydrogen orthophosphate were synthesized using a solution method with the aid of ultrasonication for uniform dispersion of the materials in the polymer composite. The flammability and thermal properties for the new composites were studied. The rate of burning was recorded 28.5 mm/min for the composite compared to 46.5 mm/min for virgin polymer. Interestingly, when rice husk ash was added to the previous composite the rate of burning was reduced to 17.4 mm/min which confirmed the synergism. When multiwalled carbon nanotubes (MWCNTs) were incorporated to the previous composite the rate of the burning of the new nanocomposite decreased to 13.5 mm/min achieving 71% reduction in the rate of burning of the nanocomposite and enhanced synergistic effect was observed in the nanocomposite. The rice husk silica produced was elucidated using FTIR spectroscopy. The different composites materials were characterized using thermal gravimetric analysis, UL94 flame chamber. The dispersion of carbon nanotubes, rice husk silica and diammonium hydrogen orthophosphate were studied using scanning electron microscopy (SEM).