The previous studies suggest that hydrogen bond between chlorinated polypropylene (CPP) and polyaniline (PANI) plays a prominent role in the decision of polypropylene/CPP/PANI composites' electric property. In situ Fourier-transform infrared spectra were employed to detect and identify the relationship between the hydrogen bond and the temperature. Two kinds of hydrogen bond were carefully studied in the nitrogenhydrogen bond (N-H) stretching, sulfuroxygen double bond (S=O) stretching, and carbonchlorine bond (C-Cl) stretching regions, using an iterative least-squares computer program to obtain the best fit of spectra. The ratio of absorptivity coefficients and the mole fraction of the free and two kinds of H-bonded N-H were calculated. There exists an apparent turning point in the curves of the relationship between the fraction of two kinds of H-bonded N-H and temperature. This phenomenon also exists in the S=O stretching region, and the turning point is at about 60 degrees C. The mole fraction of H-bonded C-Cl decreases, and that of free C-Cl increases with increasing temperature. The enthalpy gap between the H-bonded N-H center dot center dot center dot center dot center dot O=S and the H-bonded N- H center dot center dot center dot center dot Cl=C dissociation was also obtained as 23.2 KJ/mol. POLYM. ENG. SCI., 52:2627-2636, 2012. (C) 2012 Society of Plastics Engineers