Study on the relationship between evolved gases in carbonization of stabilized polyacrylonitrile fibers with 12,000 filaments and their mechanical properties

In this study, we proposed a carbonization mechanism of stabilized polyacrylonitrile (PAN) fibers with 12,000 strands (12 k) as a function of heating rates through the in-situ thermogravimetric analysis and mass spectroscopy during carbonization process. In order to simulate an actual manufacturing process of carbon fibers (CFs), stabilized fibers were carbonized at up to 1200 °C through heating rates of 20, 25, and 30 °C/min. We investigated the relationship between the rates and the structural and mechanical properties of the CFs analyzed by X-ray diffractometer and Raman spectroscopy. The high heating rate leads to higher decomposed temperature and carbonization yields of the stabilized fibers compared to the other rates. Therefore, it is believed that the structural and mechanical properties of the CFs could be improved by suitable removing uncyclized atoms under 500 °C and inducing intermolecular bonding between the stabilized PAN polymers above 1000 °C.