In this study, 20 recipe rubber compounds were prepared by using SMR-20 type of
natural rubber and SBR-1502 type of styrene–butadiene rubber in different levels (0, 25, 50,
75 and 100) pphr and each recipe reinforced with carbon black at different ratio (20, 40, 60
and 80) pphr (part per hundred). The mechanical properties – such as tensile strength, tensile
modulus at 100% elongation, elongation at break, hardness, wear and resilience were studied.
The results show that the tensile modulus at 100% elongation (MOD 100) and ultimate tensile
strength increase with increasing of carbon black loading level and maximum value was
achieved at 60 pphr (carbon black), while elongation at break decreased with increasing of
carbon black loading for all recipes. All these properties increased with increasing of NR to
SBR. The hardness and wear properties of the NR/SBR blends with the increment of SBR
percentages and carbon black loading level were greatly enhanced. The resilience decrease
with increase of carbon black loading for all recipes and with the increase of SBR to NR