Impact of spinning conditions on the diameter and tensile properties of mesophase petroleum pitch carbon fibers using design of experiments

Abstract The structure of a mesophase pitch carbon fiber evolves in spinning and is perfected through stabilization and carbonization. Thus, it is crucial to control extrusion variables to form standard carbon fibers. Design of experiments was employed in melt spinning to investigate the influence of three process variables on the diameter of petroleum-derived pitch filaments. Optimized conditions were validated in an experiment that produced filaments with average diameter of 14 μm. Pitch filaments with different thickness were thermally treated to verify structure discrepancies and quantify the relation between mechanical properties and fiber’s diameters. Diameters smaller than 45 μm could be stabilized in air. Thinner fibers reached average strength of 1.4 GPa and 150 GPa modulus, thicker fibers only supported 120 MPa with 65 GPa modulus.