Effects of oxidation treatment by KClO3/H2SO4 systems on the chemical, crystal and microscopic structures of polyacrylonitrile fibers

Abstract

The effects of various KClO₃ concentrations and durations on polyacrylonitrile (PAN) fibers were investigated. The oxidation treatment of PAN fibers (PFs) in a KClO₃/H₂SO₄ system is a new pretreatment method for carbon fiber oxidation stabilization. Wettability (droplet shape), chemical structures (Fourier transform infrared spectroscopy [FT-IR]), crystal structures (wide-angle X-ray diffraction), microscopic structures (scanning electron microscopy), and chemical components (X-ray photoelectron spectroscopy) were analyzed. The PFs had the smallest contact angle and the best wettability when the KClO₃ concentration was 15 wt%. FT-IR analysis showed that the absorption peak of the fibers was the lowest when the KClO₃ concentration was 15 wt%. The peak intensities of MPFs-15-60 and MPFs-15-90 at 2θ = 17° and 2θ = 29°, respectively, were close and lower than the peak intensities of others. The number of grooves present on the fiber surface decreased when the KClO₃ concentration was 15 wt%. As the KClO₃ concentration increased, the elemental C content decreased and the elemental O content increased. MPFs-15-60 had a low C content and the highest O content, indicating that it had the highest degree of oxidation. The best sample for PF oxidation treatment with KClO₃ was MPFs-15-60. The optimal processing conditions were a KClO₃ concentration of 15 wt% and duration of 60 min.