FTIR-ATR (Fourier Transform Infrared-Attenuated Total Reflectance) spectroscopic analysis was used to study the kinetics of the formation of the polyurethane foam, which was prepared by reacting a mixture of lignin-aminated polyol (LAP) and glycol (PEG) with diphenylmethane diisocyanates (MDI-50) in the presence of water as blowing agent. The crosslinking reactions were followed by monitoring the change of the absorbance of the NCO group at 2270 cm-1 in FTIR-ATR spectra. The apparent activation energy (Ea) calculated according to n-th order reaction model was 16.44 kJ/mol, and the frequency factor (A') was 2.69 min-1. Furthermore, the crosslinking reaction is approximated to be a first-order reaction. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012