Effect of PAN pre-oxidized fibers radial structure distribution characteristics on graphite fibers

Abstract

The radial structure of PAN-based graphite fibers is one of the important influencing factors to achieve high strength and high modulus. Effectively regulating and optimizing the radial structure distribution characteristics of graphite fibers has important guiding significance for the preparation of high-performance graphite fibers. The effects of PAN pre-oxidized fibers radial structure distribution characteristics on graphite fibers radial structure distribution characteristics and mechanical properties were studied by carbonizing and graphitizing pre-oxidized fibers with different radial distribution characteristics. The results show that the radial structure of graphite fibers is inherited from the radial structure of PAN pre-oxidized fibers. After carbonization and graphitization, the pre-oxidized fibers with more conjugated structures have a higher degree of graphitization, which are conducive to improving the mechanical properties of the fibers. However, the excessively high pre-oxidation temperature not only increases the oxygen-containing structure in the fibers, but also makes the radial structure of the graphite fibers too different, resulting in a decrease in the compactness of the graphite fibers structure and shear stress between the sheath and core, which reduces the fibers carrying capacity and impairs mechanical properties.

Keywords

• pre-oxidized fiber
• graphite fiber
• radial structure
• distribution characteristic