The thermal stability and pyrolysis behaviors of polyimide (PI) foam derived from 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA)/4,4'-oxydianiline (4,4'-ODA) in air and in nitrogen were studied. The decomposition products of PI foam were analyzed by thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR). Several integral and differential methods reported in the literatures were used in decomposition kinetics analysis of PI foam. The results indicated that the PI foam was easier to decompose in air than in nitrogen, with similar to 55% residue remaining in nitrogen versus zero in air at 800 degrees C. The main pyrolysis products were CO2, CO, and H2O in air and CO2, CO, H2O, and small organic molecules in nitrogen. The different dynamic methods gave similar results that the apparent activation energies, pre-exponential factors, and reaction orders were higher in nitrogen than those in air. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1680-1687, 2010