Enhancement of thermal and mechanical properties of high density polyethylene using commercial clays

The properties required for rainwater containers and pipes were discussed. This work aimed at improving the overall properties of high density polyethylene (HDPE) with commercially available clays for rainwater harvesting system. Ten types of clay were respectively incorporated into HDPE matrix via melt extrusion. Morphological, structural, mechanical and thermal characterizations were performed. The findings show that the clay dispersion state was determined by the thermal stability of their organomodifier. Thermally stable organomodifier dimethyl di(hydrogenated tallow) (2M2HT) prevents clay aggregation and contributes to clay intercalation. The incorporation of high-aspect-ratio clays containing a thermal stable organomodifier improved the mechanical properties of HDPE. Increased Young’s modulus and tensile strength were obtained by addition of appropriate clays. The oxidative induction time (OIT) of clay-HDPE blends were dramatically decreased by the presence of organomodifiers and contaminants. Only unmodified clay with a low impurity content showed less reduction in OIT values. Lastly, it was found that the thermal degradation behavior of blends was related to the dispersion state and the impurity content of clays.