Abstract A two‐roll mill was used to make rubber‐rubber blends (RRBs) of natural rubber (70phr) and butadiene rubber (BR) (30phr) with 10, 20, 30, 40, and 50phr of carbon black (CB). All of the blend composition's cure, morphological, and mechanical characteristics were tested and described in the paper. In contrast to neat RRB, time values dropped, and maximum torque increased for CB filled RRBs, according to the rheo‐curve. In contrast to neat RRB, the mechanical properties of CB filled RRBs improved. The “partitioning of CB” within the BR phase in CB filled RRBs is associated to an increase in mechanical properties. The particle size distribution curve for CB filled RRBs obtained using a transmission electron microscope agrees well with their mechanical properties. Readers would benefit from a correlation between “partitioning of CB” driven by “quantitative features” and “mechanical properties” of CB filled RRBs.