Integration of experimental methods and molecular dynamics simulations for a comprehensive understanding of enhancement mechanisms in graphene oxide (GO)/rubber composites

Graphene oxide exhibits great applications in the rubber industry due to its unique two-dimensional nanosheet structure, significant specific surface area, good barrier property, and high reactivity. However, different rubbers, such as carboxylated nitrile butadiene rubber, natural rubber, and styrene butadiene rubber, have different interactions with graphene oxide, which have a great influence on the reinforcement effect of graphene oxide on the rubber matrix. In this work, the enhancement mechanism of graphene oxide on carboxylated nitrile butadiene rubber, natural rubber, and styrene butadiene rubber was studied and the relationship between the microstructures and properties of GO/rubber nanocomposites was investigated by combining experiments with molecular dynamics simulation. The simulation results showed that graphene oxide had the best compatibility and the strongest interaction with carboxylated nitrile butadiene rubber, resulting in the largest binding energy and the smallest fractional free volume, mean square displacement, and the change of adhesive energy. The solvent resistance and mechanical properties of carboxylated nitrile butadiene rubber were improved by introducing graphene oxide, which was consistent with simulation results. This study provides a new way to explore the macroscopic properties of rubber nanocomposites at the molecular level.