Preparation And Characterization Of Carbon Fiber Based On Coal Pitch

Carbon fibers were considered to be high strength materials having great importance in variety of specialized applications,such as national defence, clinical use,aerospace,industry and sports.The pitch-based carbon fibers could be prepared from raw pitch which be treated by extraction,condensation,spinning,oxidation and canbonization.It had promising future due to ample raw materials and low cost.In this study,pitch precursors were prepared from coal pitch in the presence of the catalyst of borontrifluoride(BFDE) and the co-catalyst of diethyletherate (NB). Precursors showed an increase in aromaticity and softening point from the raw materials. It also showed good spinnability.Subsequently,the precursors were spun and carbonized to be carbon fiber.From elemental analysis,it indentified that through the quinoline extraction, condensation reaction, high temperature carbonization,the carbon content of carbon fiber increased to 96.56%,compared by 76.45% of raw coal pitch.Analysis of rheological properties proved that molecular volume of pitch precursor enlarged after condensation reaction with the activation energy of the viscous flow increased 2.5 times.The precursor mostly was consisted of fused aromatic. Optimum spinning temperature field of pitch precursor was 140℃～150℃, and in this temperature range,the viscosity of pitch precursor could be stable at 100Pa·s. TG-DSC showed that fragmentation reaction, aromatization and carbon chain re-engineering occurred during carbonization. Tensile strength of carbon fiber carbonized at 1000℃was 4140Mpa.SEM showed that the diameter of carbon fiber was 10μm.the surface of CF was smooth and free of defects and the internal density was high. There were no obvious focal points of stress in the surface and edges of cross section.So it ensured excellent mechanical properties in structure.In addition,carbon fiber had good crimp ability.TEM proved that carbon fiber was nearly composed of pure carbon. The overall orientation of carbon lattice disordered but local area ordered.XRD showed poor crystallinity of carbon fiber.FT-IR indentified that after carbonization, methylene group connectting aromatic ring was broken and divorced from aromatic system.cross-linked netlike structure were destroyed, more and more aromatic ring getting closer to form condensed aromatics. Figure 20 table 8 reference 53...