Crosslinked nitrile-butadiene rubber (NBR)/hindered phenol composites were successfully prepared by mixing tetrakis [methylene-3-(3-5-ditert-butyl-4-hydroxy phenyl) propionyloxy] methane (AO-60) into NBR with 35% acrylonitrile mass fraction. The structural and mechanical properties of the NBR/AO-60 composites were systematically investigated by using differential scanning calorimeter, XRD, Fourier transform infrared, scanning electronic microscope, dynamic mechanical analyzer, and tensile testing. The results indicated that the AO-60 changed from crystalline form into amorphous form, and most of the AO-60 molecules could be uniformly dispersed in the NBR matrix. The glass transition temperature (T-g) of NBR/AO-60 composites increased gradually with increasing content of AO-60. The increase in T-g could be attributed to the formation of a strong hydrogen bonding network between the AO-60 molecules and the NBR matrix. Unlike the pure NBR, the NBR/AO-60 rubber composites had only one transition with a high loss factor. With increasing content of AO-60, the loss peak shifted to the high temperature region, the loss factor increased from 1.45 to 1.91, and the area under the tan delta versus temperature curve (TA) also showed a significant increase. All these results were ascribed to the good compatibility and strong intermolecular interactions between NBR and AO-60. Furthermore, all NBR/AO-60 composites exhibited higher glass transition temperatures and tensile strength than NBR, and they had other desirable mechanical properties. They have excellent prospects in damping material applications. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3696-3702, 2012