Pitch-based carbon fiber of high compressive strength prepared from synthetic isotropic pitch containing mesophase spheres

Two pitches containing mesophase spheres were prepared from a synthetic isotropic naphthalene pitch at 360°C and 375°C so as to contain spheres of different diameters. Both pitches were smoothly spun into thin fibers, which were converted into carbon fibers through stabilization, carbonization and graphitization. The fiber from the pitch with finer spheres exhibited a higher compressive strength, which reflected smaller microdomains, smaller, and thinner fibrils, being different from both isotropic and anisotropic pitch fibers. The isotropic fraction of the pitch appears to give areas of smaller microdomains. The fiber exhibited intermediate values in graphitic parameters between those of isotropic and anisotropic pitch-based fibers.