Abstract
Coal tar pitch was air-blown under the various pressures and temperatures to investigate their roles on the properties of isotropic pitch fiber precursor derived from the pitch. The quality of the precursor pitches was evaluated in terms of their spinning continuity, stabilization reactivity and strength of the resultant carbon fibers. The pitches were also characterized by means of solvent fractionation and NMR spectroscopy. Lower pressure and temperature were confirmed to produce better precursor pitches for the general purpose carbon fiber of higher quality. Although the yield of the pitch was low. Efficient removal of lighter fraction without excess condensation of heavier fraction favored the quality of the pitch. The distillation before the air-blowing to remove lower boiling substances was found also effective to give better precursor pitch for the general purpose cabon fiber of higher quality. In contrast, the prehydrogenation allowed development of mesophase and decreased the 13-resin content in the air-blown pitch, being not recommended in the pretreatment.
