Thermal Behavior in Stabilization of Large Tow PAN-based Carbon Fiber

In this study, we investigated stepwise stabilization process of 48 k filaments PAN precursor to observe thermal behavior of PAN fibers. We also controlled parameters such as oven temperature, air flow direction, velocity, thermal residence time, and tow size to optimize stabilization process for large tow carbon fibers. FTIR, elemental analyzer, density column, X-ray diffractometer were used to evaluate stabilization degree and chemical structural evolution during thermal stabilization. The oxidation process of PAN fibers makes cross-linking reaction more easier between intermolecular chains and enduces cyclization reaction of acrylonitrile. In addition, the degree of air diffusion into fibers affects the mechanical properties of the final carbon fiber. The carbon fiber with ca. 10% of oxygen content and 1.40 g/cm(3) of density showed the best mechanical properties with 2.5 GPa tensile strength and 214 GPa tensile modulus.