Effect of Montmorillonite Clay on the Burning Rate of High-Impact Polystyrene

The effect that montmorillonite clay has on the burning rate of high impact polystyrene (HIPS) is examined. Two clays are considered a pristine montmorillonite (MMT-Na+) and a montmorillonite clay intercalated with triphenyl phosphite (TPP). In addition to the burning rate tests, mechanical, impact and rheological properties are determined. Results show an increase of 55% in the burning rate of the nanocomposite when the neat MMT-Na+ clay is added. Thermal measurements indicate a diminishing HIPS decomposition temperature as the MMT-Na+ clay concentration rises. On the other hand, when TPP is incorporated in MMT-Na+ (MMT-i-TPP) and the clay is added to HIPS, a substantial reduction (42%) of the burning rate is observed, while the mechanical properties are kept at the level of those of the original HIPS. The system HIPS-MMT-i-TPP presents a steeper reduction in the viscosity as compared to HIPS in the high-temperature range.