Influence of montmorillonite as secondary filler on the properties of carbon nanotube / high density polyethylene nanocomposites

Abstract

In this study, the influence of secondary filler on the dispersion of carbon nanotube (CNT) reinforced high density polyethylene (HDPE) nanocomposites (CNT/HDPE) was investigated. In order to understand the mixed-fillers system, montmorillonite (MMT) in addition with maleic anhydride grafted high density polyethylene (PE-g-MA) was added to CNT/HDPE nanocomposites. It was followed by investigating their effects on the thermomechanical, rheological and morphological properties of the aforesaid nanocomposite. Incorporation of 3 wt% each of MMT and PE-g-MA into CNT/HDPE nanocomposites resulted in the increase values of the tensile and flexural strength (32% increase in both), as compared to that of pure HDPE matrix. Thermal analysis results showed an improvement in thermal stability of the formulated nanocomposites. The initial decomposition temperature (Ti) for nanocomposite with 9 wt% of MMT and 3 wt% of PE-g-MA increased from 265 oC (Ti for neat HDPE matrix) to 296 oC. Addition of MMT into CNT/HDPE nanocomposites had also increased the rheological properties, indicating a dominant elastic response. Significant increase in loss modulus, storage modulus and complex viscosity were observed upon addition of PE-g-MA, whereas Tan ? was found to be reduced. This might be due to better interfacial adhesion between MMT and HDPE phases that attributed to the elastic dominance. Improvement in dispersion of CNT upon addition of MMT and PE-g-MA was further supported by the morphological analysis. Transmission electron microscopy (TEM) images revealed that larger aggregates of CNTs were disappeared upon addition of these two components leading to the enhancement of thermo-mechanical properties for such nanocomposites.