This study investigated the effect of carbon black (CB) filler loading on mechanical and rheological properties of natural rubber (NR)/styrene-butadiene rubber (SBR)/nitrile butadiene rubber (NBR) ternary rubber nanocomposites. The nanocomposites were prepared using a melt mixing method. Four different samples with different filler loadings namely S2 (15 phr), S3 (30 phr), S4 (45 phr), and S5 (60 phr) were prepared in this work. The mechanical properties of these samples were investigated such as tensile strength, stress at 100, 200, and 300% elongations, elongation at break %, tear strength, compression set, compression stress, and crosslink density. Results indicate that minimum torque, maximum torque, tensile strength, stress at 100, 200, and 300% elongations, elongation at break %, tear strength, compression set, compression stress, and crosslink density were increased while the scorch time, cure time, cure rate index, elongation at break %, swelling coefficient, and filler–rubber interaction decrease with increasing CB loading. The higher value of tensile strength for these samples was S4 (loading with 45-phr CB). Therefore, had higher stiffness compared to the other content ratio. Additionally, S4 showed 233.58% increment in tensile strength. These results showed that the optimum filler loading can increase the compatibility between CB and NR/SBR/NBR. These results were confirmed by scanning electron microscope micrography.
