Preparation and evaluation of isotropic and mesophase pitch-based carbon fibers using the pelletizing and continuous spinning process

The purpose of this study is to investigate the potential of using a pelletized pitch in a continuous process for the economical preparation of large-scale pitch-based carbon fibers. The pitch was pelletized before spinning because the pitch powder can agglomerate in the feed throat of a screw extruder, which can render uniform heating difficult. Using the pelletized pitch in a single-screw extruder spinning apparatus, the pitch fiber can be spun to a great length as long as the amount of pitch pellets is sufficient. To evaluate the benefits of using pitch pellets in the continuous carbon fiber spinning process, isotropic and mesophase pitch fibers were prepared by both the conventional batch process using pitch powder and continuous process using pitch pellets. Even with a huge difference in the thermal energy used, the carbon fibers prepared using the pelletized-pitch-based continuous process had better tensile properties than those prepared using the conventional process. This suggests that the continuous process using pitch pellets has the potential to be an economical large-scale process for carbon fiber preparation.