Exploring the Reinforcement Mechanism of Carbon Black in Natural Rubber: Insights From Surface Morphology and Molecular Chain Rigidity

ABSTRACT Carbon black (CB) is extensively applied in the tire manufacturing industry. Nevertheless, due to the sophisticated clustered structure of CB aggregates, it is arduous to elucidate the boundary between CB and rubber. Hence, we do not have a full understanding of how CB reinforces rubber. Quantitative analysis of the interface thickness in NR/CB composites was carried out by employing atomic force microscopy (AFM). Low‐field nuclear magnetic resonance (LF‐NMR) was used to characterize the molecular chain rigidity of NR/CB with various specific surface areas. The results indicate that the high SSA of CB arises from its intricate topological architecture characterized by a branched aggregate morphology. This structural complexity facilitates enhanced interfacial engagement with the NR matrix, leading to the formation of extended nanoscale interfacial regions and localized restrictions on polymer chain mobility.