The article portrays the synergistic reinforcement of new generation nanofillers such as silicon carbide nanofibers (SiCs), carbon nanotubes (CNTs), and graphite nanofibers (GNFs) when used along with carbon black (CB) in a typical tire tread composition. The unique synergism in these composites, which were fabricated by a liquid phase mixing method, was reflected in their enhanced failure resistance and dynamic mechanical properties. At 4 phr loading of the nanofiber, the tensile strength, tear strength, modulus at 300% elongation, storage modulus, rolling resistance, and abrasion resistance were improved by 29, 45, 36, 110, 15, and 14%, respectively. The role of nanofibers in the development of a hybrid microstructure was investigated by scanning and transmission electron microscopy. Tribological characteristics were studied using a Laboratory Abrasion Tester (LAT 100), and the abrasion loss of the samples was correlated with energy dissipation occurring during the process. The fatigue properties indicated the ability of the CB-nanofiber dual filler system to arrest crack growth. The study also serves to establish a correlation between the wear loss and fatigue properties of the hybrid nanocomposites containing different fibrous nanofillers. A mechanism of reinforcement by hybrid fillers is proposed.

Hybrid nanocomposites were prepared by predispersion of new nanofibers such as aramid nanofibers, carbon nanotubes, silicon carbide nanofibers (SiC), cellulose nanofibers, and graphite nanofibers in natural rubber (NR) latex prior to melt mixing in an internal mixer to ensure the exquisite dispersion of nanofibers in NR. The competency of these nanofibers in reinforcing NR as well as enhancing its barrier properties has not been widely investigated. The fabricated nanocomposites showed enhanced curing as well as mechanical and dynamic mechanical properties. Morphology of the composites was analyzed through electron microscopy. The increase in tortuosity created by the presence of the hybrid filler system consisting of carbon black and nanofibers was studied using permeability models. At higher tearing energies, it was seen that the nanofiber-reinforced composites showed comparable crack growth properties; however, at lower energies, the fabricated composites exhibited higher crack propagation rates compared with the control compound when studied using a tear fatigue analyzer. The improved mechanical, dynamic mechanical, and barrier properties along with comparable fatigue crack growth properties offer an opportunity to apply these systems in high-end applications such as a thinner tire inner liner with a higher NR blend ratio, which can result in improved processability and reduced hysteresis, fuel consumption, and cost.

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