Influence of carbon black surface characteristics on CB-NR interfacial interaction: Molecular simulation and experimental study

Carbon black (CB) is the most widely used reinforcing filler in rubber industry, but the effects of CB surface characteristics on interfacial interaction of CB-filled rubber composites are still not fully described. Combined the experimental and molecular simulation techniques, the aim of this study is to individually investigate the influence of various CB surface characteristics, such as surface area, surface crystallite size, roughness and surface energy, on CB-natural rubber (NR) interfacial interaction to obtain a deep interpretation on the properties of rubber composites. Experimental results showed that the specific surface area is the primary factor affecting overall CB-NR interaction, followed by filler network. Meanwhile, CB surface model with different roughness based on experimental parameters were constructed, and the simulation results revealed that CB-NR interfacial interaction mainly occurred at the interface 2–3 nm. The binding energy distribution on CB surface was analyzed, and rough region is weaker than crystal region and amorphous region. The strongest binding sites are located at the junction of rough region and amorphous region. The results in this study are expected to provide a theoretic guide for optimizing the CB characteristics and developing new rubber-grade CB.