Burning Rate, Mechanical and Rheological Properties of HIPS-PET and Clay Nanocomposites

Abstract

We analyze the effect of montmorillonite clay nanoparticles on the burning rate (BR), mechanical and rheological properties of high-impact polystyrene (HIPS) and blends of polyethylene terephthalate (PET) and HIPS produced by a twin-screw extrusion process. It is found that the BR of the HIPS-PET system is considerably reduced at relatively high clay concentrations. On the other hand, the increase in clay concentration in the HIPS matrix none leads to an unexpected rise in the BR. The degradation temperature is determined by measurements of complex viscosity as a function of temperature. It is found that degradation temperature decreases with clay concentration, particularly in the HIPS-PET-clay nanocomposite, diminishing by 28°C with respect to that of HIPS at high clay contents. This low degradation temperature means that a char layer is formed at lower temperatures, so the BR decreases as well. Mechanical properties are also affected, such as the fracture strain.