A two-roll mill machine was used for the grafting of p-aminophenol (pAP) onto natural rubber (NR). The prepared NR graft p-aminphenol (NR-g-pAP) was characterized by H-1 NMR and IR spectroscopy techniques. The goal of this article is to study the effect of commercial antioxidants, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD) and N-phenyl-N'-isopropyl-p-phenylenediamine (IPPD), and the prepared NR-g-pAP, on the mechanical properties of acrylonitrile-butadiene (NBR) vulcanizates, the fluid compatibility of NBR vulcanizates, the hydraulic brake and clutch fluid dot, the diffusion out for NBR vulcanizate components, and the compression recovery of NBR vulcanizates. This study indicates that the NBR copolymer vulcanizate which contains the prepared NR-g-pAP has good protection against mechanical stress and the diffusion out of NBR vulcanizate components. The 6PPD and the prepared NR-g-pAP ameliorates the fluid compatibility of the oil seals, which is based on NBR as elastomer, and the hydraulic brake and clutch fluid dot. (c) 2006 Wiley Periodicals, Inc.