Mechanical and rheological properties of partial replacement of carbon black by treated ultrafine calcium carbonate in natural rubber compounds

The present research aimed to develop natural rubber (NR) hybrid composites reinforced with treated ultrafine calcium carbonate/carbon black (CC/CB). The influence of CC/CB with various filler ratios (50/0, 40/10, 30/20, 20/30, 10/40 and 0/50) on mechanical properties and cure characteristics of the vulcanizates was investigated and their reinforcing efficiency was compared aiming to achieve the best ratio for CB partial substitution as compared to composites with CC and CB incorporated separately. The CC 30 /CB 20 composites reached around to 17 MPa similar strength at break response compared to CC 0 /CB 50 (16.83 MPa). Elongation at break increased 48% in relation to CC 0 /CB 50 . Hardness maintain similar values compare to high concentration of CB composites. Crosslink density results revealed similar chain number in rubber matrix representing better interaction between CC/CB. Scanning electron microscopy studies also reveal a good filler dispersion between filler particles and matrix. The results shown that the new material can be an alternative filler for partial substitution of CB conserving mechanical properties.