Air-blowing reactions of pitch: I. Oxidation of aromatic hydrocarbons

In order to deepen our understanding of the air-blowing reaction of pitch as a precursor of carbon fiber, aromatic hydrocarbons having 2 to 3 rings were selected as pitch models, and structural analyses of their air-blown products were conducted using FD-MS, GC-MS, NMR, and FT-IR spectroscopies. Alkyl-substituted aromatic compounds polymerized with methylene, biphenyl-type, and ether bonding, leading the methylene to partially change into carbonyl during the air-blowing reaction. Therefore, the pitches containing alkyl-substituted compounds are the most effective source materials for raising the softening point, increasing molecular weight, and suppressing anisotropic texture. The properties of the air-blown products were characterized by, and dependent mainly upon, the crosslinked carbon and the condensed aromatic carbon formed by the air-blowing reaction.