Influence of partial substitution for CB with MWNTs on performance of CB‐filled NR composites

The effects of substituting carbon black (CB) with multiwall carbon nanotubes (MWNTs) on the structure and properties of natural rubber (NR)/CB composites is explored. Compared with NR/CB composites, NR/MWNTs/CB presents better filler dispersity and dynamic properties of the MWNT up to a certain concentration, as confirmed by scanning electron microscope, dynamic mechanical analyser and rubber processing analyser. Sample with 1 phr MWNTs shows obviously the highest tensile strength, 28.60 MPa, and almost the lowest heat build‐up, only 9.6°C, and it is attributed to that not only large cross‐link density and better filler dispersity but also high effective elasticity and large filler–rubber interaction. However, when the concentration is much higher, MWNTs tend to aggregate and lead to the poor efficiency to enhance the dynamic properties of rubber composites or even deteriorate the properties.