Modified oxidative thermal treatment for the preparation of isotropic pitch towards cost-competitive carbon fiber

A modified oxidative thermal treatment was developed to increase the softening point of a pitch precursor while minimizing the pitch yield loss. An O-2/N-2 mixed gas was used as the reaction gas, and the softening point and pitch yield variations were measured at different 02 concentrations. As a result, when softening point increased from 130 to 249 degrees C, the pitch yield remained almost constant (only 0.6% drop). Structural analysis performed via MALDI-TOF, FTIR, and H-1 and (NMR)-N-13 showed that condensation reaction between pitch molecules in the presence of O-2-containing gas followed a different mechanism depending on the O-2 concentration. In addition, the precursors were spun into pitch fibers and carbonized at 1100 degrees C. During the spinning, they exhibited excellent spinnability without breakage for more than 10 min of spinning. The obtained carbon fibers showed high tensile strengths comparable to that of a commercial isotropic-pitch-derived carbon fiber (0.83 GPa). The current study showed that the modified thermal treatment is useful for the preparation of cost-competitive pitch precursors suitable for carbon fiber production. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.