Interaction between thermal stabilization temperature program, oxidation reaction, and mechanical properties of polyacrylonitrile (PAN) based carbon fibers

Thermal stabilization is a very time-consuming process from PAN fibers to carbon fibers and seriously affects the structure and properties of the final carbon fibers. In this study, the thermal stabilization of PAN fibers is accomplished through two steps, taking 12 k PAN fibers as an example. That is, firstly, the preliminary thermal stabilization is done by optimizing the temperature range (220–240 °C) to achieve the rapid establishment of the trapezoidal structure. Then, the completed thermal stabilization is done by holding at a lower temperature (240 °C) to refine the oxidized structure. Discussions focused on the establishment of the optimized temperature range in the preliminary thermal stabilization and the effect of insulating at different temperatures during the completed thermal stabilization on the development of the structure and properties of the carbon fibers. It was confirmed that the use of this process to accomplish thermal stabilization of PAN fibers reasonably reduced the process time and energy consumption for thermal stabilization and improved the mechanical properties of the final carbon fibers. Moreover, it is applicable to optimize the thermal stabilization temperature program for all commercially available PAN fibers with different tow specifications and properties without any additional conditions.