The change of chemical structure of polyacrylonitrile at thermal stabilization

Oxidative stabilization is a critical step in the conversion of polyacrylonitrile (PAN) fibers to high performance carbon fiber. The oxidative stabilization stage includes different chemical reactions, which are cyclization, dehydrogenation, aromatization, oxidation and cross linking. In this work, the effect of temperature on chemical structure of fibers during oxidation step was investigated by measuring of fiber density and fourier transform infrared (FTIR) analysis. The results showed that by increasing the temperature, the intensity of nitrile band at 2242cm-1decreased and a peak at 1600cm-1 was appeared indicating the cyclization and dehydrogenation reaction, respectively