Structural Evolution of Lyocell Fiber During Thermal Stabilization and Carbonization

To produce bio‐based carbon fibers (CFs), evolution of structure is studied for lyocell fiber (LF), which is a cellulose fiber prepared by dry‐jet wet spinning, subjected to thermal stabilization and carbonization. The effect of stabilization temperature and time on composition, structure, and thermal stability of LF is investigated using elemental analysis, Thermogravimetry (TG) and X‐ray diffraction. The content of C in the stabilized LF increases with increasing stabilization temperature and time. The original cellulose II crystal in LF collapses when the carbon content reaches 53.6% during stabilization. At 240°C for 30 min, the carbon yield at 700°C rises due to the thermal stabilization of LF, reaching a maximum value of 53.17%. LF‐based CF, with a tensile strength of 546 MPa and a tensile modulus of 56.8 GPa, is continuously prepared by carbonizing the stabilized LF at 1350°C.