Fourier transform infrared (FTIR) thermal analysis was utilized to study the temperature dependence of hydrogen bond in Fe-octacarboxyl acid phthalocyanine (Fe-OCAP)/polyurethane (PU) blends. Two regions in the FTIR spectra were concerned to investigate the difference of the degree of hydrogen bond in the samples: the NH stretching region (3210-3460 cm(-1)) and carbonyl stretching region (1680-1760 cm(-1)). It was found that the average strength of hydrogen bond in the modified samples was stronger than that in pure PU. With increasing Fe-OCAP content, the hydrogen bonded NH and carbonyl groups were increased, while with increasing temperature they decreased. The equilibrium between free and hydrogen bonded carbonyl groups was discussed. The dissociation enthalpy for hydrogen bonded carbonyl of the samples was increased with increasing Fe-OCAP content. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2265-2271, 2013