Structure and stabilization studies of mesophase pitch

Abstract

Stabilization is a key stage in the production of carbon fibres from mesophase pitch, as it renders the mesophase infusible during the subsequent carbonization. Mesophase pitches have been made from Ashland 240 (A-240) pitch by heating at 400 °C for 2 h. The mesophase-pitch powders were stabilized by two methods: (a) heat treatment in air, and (b) heat treatment in the presence of dicumyl peroxide [DCP, C₁₈H₂₂O₂, bis(1-methyl-1-phenylethyl) peroxide] in N₂ atmosphere, both at 250 °C for 5 and 10 h. Changes in IR reflectance intensities of carbonyl (–CO–, 1690 cm^–) and aliphatic C–H (3000–2850 and 1430 cm^–1) characteristic peaks were observed as a result of stabilization. The IR spectral intensities of aryl alkyl ether peaks at 1200–1275 cm ^–1 increased with air stabilization. DCP is shown to be a good stabilizing agent for mesophase pitch without incorporating oxygen into the resulting carbonaceous materials. The microstructures of mesophase-pitch powder after stabilization with air or with DCP did not differ from each other in spite of the differences in FT-IR spectra.