Structural characterization of high-density polyethylene nanocomposites: effect of compatibilizer type and high aspect ratio organoclay platelets

This research focuses on the possibility of improving properties of high-density polyethylene-based nanocomposite films for packaging applications, using a high aspect ratio layered silicate named fluoromica. Three different compatibilizers [ethylene vinyl acetate copolymer and two grades of maleic anhydride grafted high-density polyethylene (HDPE-g-MA) with different melt flow indices] were examined to explore the effects of compatibilizer polarity and molecular weight on the state of nanoclay dispersion. Owing to the direct correlation between nanocomposites morphology and rheological behavior, a quite extensive survey of the role of different material variables was carried out via measuring rheological properties in linear viscoelastic region. Percolation threshold ( (phi_{text{p}}) ) were determined by analyzing the improvement in dynamic viscosity in low-frequency region and also, by means of a predicted mathematical model obtained from experimental design. It was found that the HDPE-g-MA compatibilizers result in lower (phi_{text{p}}) and better clay dispersion, particularly in the case of high MFI resin. Microstructural characterization of the samples was studied by X-ray diffraction and transmission electron microscopy as well.