Molecular dynamics simulations and microscopic analysis of the damping performance of hindered phenol AO-60/nitrile-butadiene rubber composites

Molecular dynamics (MD) simulations are used to investigate the fundamental damping mechanism of the AO-60/nitrile-butadiene rubber (AO-60/NBR) composites at the molecular level in this study. The hydrogen bonds (H-bonds), binding energy, and fractional free volume (FFV) of the AO-60/NBR composites were obtained. The AO-60/NBR composite with an AO-60 content of 36 phr had the largest H-bonds, highest binding energy, and smallest FFV, all indicating a good compatibility between NBR and AO-60 and good damping performance of the AO-60/NBR composite. The experimental FTIR, and 1H-NMR results also showed that two types of H-bonds exist between the AO-60 small molecules and NBR polymer chains. Moreover, DSC and DMA were employed to characterize the compatibility between NBR and AO-60 in the composites. Phase separation between NBR and AO-60 appeared as the AO-60 content exceeded 36 phr. We hope the present study provides theoretical guidance for the design of optimum damping properties of polymer composites.