The thermal degradation of polyimide PIF2 synthesized from 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride and 4,4'-diaminodiphenylmethane was systematically and thoroughly investigated by high-resolution pyrolysis as chromatography/ mass spectrometry, thermo-gravimetric analysis, and Fourier transform infrared spectroscopy. The pyrolyzates of PIF2 were dependent on the pyrolysis temperature. Two weight-loss peaks were observed in the derivative thermogravimetric analysis of PIF2 and the first peak was related to the fluorine-containing segment (hexafluoroisopropylidene). The overall activation energy and preexponential factor were calculated through dynamic TGA with Ozawa's method. Based on the results, a thermal degradation mechanism of the PIF2 was proposed. (C) 2003 Wiley Periodicals, Inc.