Comparative study of HDPE composites reinforced with microtalc and nanotalcs: high performance filler for improving ductility at low concentration levels
Giovanni Savini, Rodrigo Lambert Oréfice
Abstract
Binary high-density polyethylene (HDPE) composites with natural microtalc (TN), semicrystalline synthetic nanotalc (NTC) and amorphous synthetic (NTA) nanotalc with 1% m/m content were prepared by mixing in the molten state in a twin-screw extruder followed by injection molding. The thermal properties were investigated by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC) and showed that the thermal stability of the composites was slightly improved with the incorporation of talcs. The morphology of composites, studied using scanning electron microscopy (SEM), revealed a good dispersion of synthetic talc in composites. The dynamic-mechanical (DMA) properties of the samples were analyzed and showed that the storage modulus was improved with the incorporation of talcs. The tensile strength and impact strength showed a moderate drop for all composites, up to 7.5% and 8.4% respectively, while the elongation at break showed a marked gain of 50% for the HDPE/NTA sample. These results suggest that NTA particles act, with great efficiency, as an internal lubricating agent or plasticizer. This research showed that NTA is a favorable filler when the main objective is to improve the ductility and the rigidity/toughness balance of HDPE and when some loss of tensile strength and impact resistance are tolerated.