This article reports on the relationship between the variation of hydrogen bonding and macroscopic properties of composites composed of hydrogenated nitrile butadiene rubber (HNBR) and 3,9-bis {1,1-dimethyl-2 [beta-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl}-2,4,8,10-tetraoxaspiro [5,5]-undecane (AO-80) Hydrogen bonding of the composites was studied by Fourier-transform infrared (FT-IR) and ultraviolet (UV) spectroscopies FT-IR spectra at room temperature revealed that the stretching vibration peak of O-H and C=O of AO-80 red shifted with increasing AO-80 content, whereas that of C=N of HNBR blue shifted only when the AO-80 content exceeded 10 parts per 100 resin (phr) At elevated temperatures, the shift was the opposite for C=O and C equivalent to N bands resulting from hydrogen bonding dissociation In the UV spectra, the E-2 band of benzene ring of AO-80 exhibited two peaks differing in shape POLYM ENG SCI, 51 201-208, 2011 (C) 2010 Society of Plastics Engineers