Effect of carbon black loading on mechanical and rheological properties of natural rubber/styrene-butadiene rubber/nitrile butadiene rubber blends

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 S-2 (15 phr), S-3 (30 phr), S-4 (45 phr), and S-5 (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 S-4 (loading with 45-phr CB). Therefore, had higher stiffness compared to the other content ratio. Additionally, S-4 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.