Processing, Structure, and Properties of Lignin- and CNT-Incorporated Polyacrylonitrile-Based Carbon Fibers

Composite fibers comprised of lignin, polyacrylonitrile (PAN), and carbon nanotubes (CNT) were successfully fabricated by gel-spinning technology. Wide angle X-ray diffraction (WAXD), infrared spectroscopy, and thermal characterizations were used to identify the effects of lignin and CNT on the physical structure and stabilization process of gel-spun precursor fibers. PAN, PAN/lignin, and PAN/lignin/CNT precursors have been converted to carbon fibers under identical stabilization and carbonization conditions. When carbonized at 1100 °C, PAN/lignin carbon fiber exhibits comparable mechanical properties to PAN carbon fiber. Raman spectroscopy studies suggested differences between the carbon fibers when lignin and CNTs were incorporated.