Preparation and characterization of pitch-based carbon fibers

A petroleum pitch was heated at 420 °C for 7 h in nitrogen to prepare a carbon fiber precursor with a softening point of 295 °C. The precursor was successfully melt-spun into fibers through a circular nozzle of a monofilament spinning apparatus, and these were then stabilized at 320 °C in air and finally carbonized at 1000 °C in nitrogen to produce carbon fibers. SEM, TGA, FT-IR, and XRD were performed to characterize the petroleum pitch, the precursor, the as-spun fibers, the stabilized fibers, and the carbon fibers. It is found that the precursor contains 70.5% mass fraction of mesophase that is aligned upon spinning, and aliphatic side chains that are beneficial to spinning. The carbon fibers have a radial core structure with a linear and bent type anisotropic texture. The maximum tensile strength of the carbon fiber is 650 MPa.