Steady Shear Behavior and Morphology of Nanocomposites Based on Polyethylene/High Impact Polystyrene Blends

Abstract

The steady shear properties and morphology of high-density polyethylene (HDPE)/high impact polystyrene (HIPS)/nanoclay (Cloisite 20A) nanocomposites with and without compatibilizer (ethylene vinyl acetate, EVA) was investigated. The rheological studies were performed by a capillary rheometer at three different temperatures; and the morphological properties of the nanocomposites were evaluated using X-ray diffractometery (XRD). The XRD analysis showed that the nanoclay was intercalated in the polymeric phases. Rheological tests showed that the prepared nanocomposites had shear thinning behavior, obeying the power law equation. At low shear rates and lower temperatures (180°C and 200°C), the addition of nanoclay decreased the shear viscosity and stress, but at higher temperature (220°C), the addition of nanoclay caused an increase in shear viscosity and stress. Viscosity was less sensitive to addition of nanoclay at higher shear rates. Flow activation energy of the nanocomposites was calculated using an Arrhenius type equation. It was concluded that the temperature sensitivity of the nanocomposites was increased by increasing of nanoclay content.