Mechanical and Tribological Studies of Halloysite Nano Clay (HNC) and Precipitated Silica Based Natural Rubber Nanocomposites

ABSTRACT This work investigates the performance of natural rubber (NR) reinforced with Halloysite Nano Clay (HNC) and precipitated silica. The main aim is to examine how the variation in HNC loading affects the mechanical, thermal, and tribological characteristics of NR, while the concentration of silica is kept constant at 30 phr. The nanocomposites are fabricated through two roll mill mixing and are characterized by tensile testing, x‐ray diffraction (XRD), scanning electron microscopy (SEM), and pin‐on‐disc tribology. Results indicates that, low HNC loadings (particularly 0.5 phr) lead to in an appreciable increase in tensile strength, (∼0.8%) and wear resistance because of the homogeneous dispersion and increased filler‐matrix interaction. Enhanced interfacial adhesion is confirmed by the smoother fracture surfaces and reduced micro voids in these composites on morphological analysis. The coefficient of friction decreased by approximately 45%–50% under varying normal loads and by nearly 55% at higher sliding velocity (5 m/s). Similarly, the specific wear rate was reduced by nearly 50%–55%, indicating the formation of a stable protective tribo‐film. Hardness increased progressively by ∼10% at higher HNC loadings, confirming the reinforcing and stiffening effect of the hybrid filler system. The tribological results showed that after the addition of hybrid fillers, the COF at 1 m/s sliding velocity was decreased by 41% and a minor reduction in the SWR also observed. Thermal conductivity was also enhanced at low HNC (5% improvement for 0.5 phr HNC loading) loadings, but reduced with excessive filler levels caused by interference in thermal pathways.