Properties enhancement in multiwalled carbon nanotube-magnetite hybrid-filled polypropylene natural rubber nanocomposites through functionalization and processing methods

The effect of multiwalled carbon nanotubes (MWCNTs)-magnetite (Fe3O4) hybrid content on the thermal, dynamic mechanical, and morphological properties of thermoplastic natural rubber (TPNR) nanocomposites was evaluated. TPNR/filler nanocomposites were prepared using a melt-blending method with a ball-milling technique as a premixed process. The acid treatment successfully shortened the lengths and disentangled the crowds of MWCNTs, which led to a better dispersion of MWCNTs in the polymer matrix, as revealed by optical microscopy and scanning electron microscopy. The improved dispersion of acid-treated MWCNTs-Fe3O4 in the TPNR matrix and the enhanced interfacial adhesion between acid-treated MWCNTs-Fe3O4 and the TPNR matrix increased the thermal stability and dynamic mechanical properties. Acid-treated MWCNTs acted as radical scavengers, which helped delay the onset of thermal degradation and hence improved the thermal stability. As expected, MWCNTs played a role as the nucleating agent in the TPNR matrix; however, the effect was more pronounced for the TPNR matrix containing pristine MWCNTs.