Achievements and challenges of computer simulation study of rubber nanocomposites

Here we summarize the current main progress in the aspect of rubber nanocomposites studied through molecular dynamics simulation, including the dispersion mechanism of nanofillers with various geometrical shapes in rubbery chains, the interfacial interaction between fillers and rubbery chains(whether the glassy polymer layer exists), the strengthened mechanism of the stress-strain behavior, the adjusting of the visco-elasticity of rubbery chains by the introduced carbon nano-springs and the mechanism accounting for the non-linear behavior of rubber nanocomposites. The simulated results indicate that there exists an optimal interfacial interaction and grafting density to achieve a good dispersion of nanofillers. For the sheet-like nanoparticles (NPs), a glassy polymer layer is possible to exist in the case of the interfacial interaction similar to hydrogen bonding. The static mechanical reinforcement results from two aspects: one aspect is the alignment and orientation of polymer chains induced by NPs, and the other aspect is the limited extension of chain bridges formed by being adsorbed onto neighboring NPs at large deformation. The introduction of nano-springs will significantly reduce the hysteresis, and direct contact between NPs as well as the network formed by each polymer chain simultaneously adsorbed onto several NPs both contribute to the formation of the non-linear behavior of the Payne effect. Elucidating these basic questions will provide significant scientific basis and theoretical guidance for preparing rubber nanocomposites with both excellent static and dynamic mechanical properties, further promoting the development of Chinese green automobile tires with high performance. Lastly, we briefly evaluate the challenges with regards to the structure-property relation of rubber nanocomposites investigated through computer simulation.