Enhanced dispersion of carbon nanotubes in high density polyethylene matrix using secondary nanofiller and compatibilizer

Abstract

In this study, we have attempted to explain the influence of secondary filler on the dispersion of carbon nanotube (CNT) reinforced high density polyethylene (HDPE) nanocomposites (CNT/HDPE). 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 effect on the thermo-mechanical, rheological and morphological properties of the aforesaid nanocomposite. Incorporation of 3 wt% each of MMT and PE-g-MA into CNT/HDPE nanocomposites resulted to the increased values for the tensile and flexural strength (32 % increase in both), as compared to the pure HDPE matrix. The thermal analysis result showed improved thermal stability of the formulated nanocomposites. The initial decomposition temperature (Ti) for such nanocomposite with 9 wt% of MMT and 3 wt% of PE-g-MA reached to 296 °C from 265 °C (Ti for neat HDPE matrix). Addition of MMT to CNT/HDPE nanocomposites also increased the rheological properties indicating a dominating elastic response. A significant increase in loss, storage modulus and complex viscosity was observed upon addition of PE-g-MA, whereas Tan d was found to be reduced. This might be due to better interfacial adhesion between MMT and HDPE phases that attributes 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 composites.