The influence of carbon nano fiber (CNF) along with organically modified nanoclay (OMMT) on the final properties of high density polyethylene (HDPE) hybrid nanocomposites has been investigated. The hybridized nanocomposites were prepared in a twin screw extruder by melt mixing to achieve better dispersion. The effect of nano fillers on the mechanical, thermal, rheological, and morphological properties has been reported. The incorporation of OMMT along with CNF slightly improved the mechanical properties of the resultant hybrid nanocomposite due to the good adhesion between the filler and matrix. On the other hand, as shown in DSC results, increasing reinforcing filler quantity has no significant influence on the thermal properties such as melting and crystallization temperatures. Thermogravimetric analysis (TGA) results have shown that increasing filler content in the hybrid nanocomposite matrix has enhanced drastically the thermal stability of the neat HDPE. Similarly, the rheological behavior of the hybrid system showed significant increase in the viscosity due to the synergetic effect. A marginal increase in moduli and complex viscosity was observed in the hybrid system, while loss tangent was found to be decreased due to the increase in the stiffness. The morphological features of nanocomposites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanoscale images showed the well dispersion of filler nanoparticles without any prominent aggregation, which further indicates the compatibilizing ability of nanofillers within the HDPE matrix.

High-density polyethylene filled with low-volume fractions of carbon nanofibers (CNFs) were prepared by melt-compounding. Two types of maleic anhydride (MAH) grafted polymers such as polypropylene-grafted-maleic anhydride (PPgMAH) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-graft-maleic anhydride (PSgMAH) were selected as compatibilizing agents for the nanocomposites. The combined effects of these agents along with carbon nanofiber on the morphological and thermal properties were examined. All the composites mainly displayed a strong XRD reflection peak at 21.6° followed by a less intensive peak at 24.0°, correspond to the unit cell structure of (110) and (200) reflection planes. Scherrer analyses of XRD data showed no significant changes in the crystalline nature of nanocomposites with respect to the neat PE. Microscopic examinations revealed that the dispersion of CNFs in the nanocomposite matrices was well dispersed within the matrix without leaving any voids. DSC analysis showed clear miscibility of CNF in the HDPE matrix and showed almost same melting temperature. TGA results showed that PE/CNF samples blended with PSgMAH exhibited higher thermal stability. The melt rheological analysis of HDPE/CNF composites was performed using an oscillatory rheometer. From flow curve, it could be understood that processing of these kinds of polymer nanocomposites is quite easy at moderate high shear rate. The oscillatory rheological analysis showed the shear-thinning behavior for the prepared composites. An improvement in the viscoelastic modulus was observed as the nanofiber concentration increases. The progress in the modulus values was attributed to the structural rigidity imparted by the high aspect ratio CNF.