High‐performance carbon fibers (CFs) are currently produced primarily from polyacrylonitrile (PAN). However, the high cost of such CFs and the environmental concerns during its manufacturing (from PAN) are stimulating research on alternative bio‐based precursors and environmentally friendly processing routes. This review summarizes the recent research studies on the pathways for converting cellulose and lignin (most abundant and renewable biomass) into suitable precursor fibers and CFs. The role of various bio‐based precursors, fiber spinning routes, and process conditions on the final properties of CFs is discussed. Although bio‐based CFs reported in the current research studies have limited strength and modulus to be considered for high‐performance aerospace applications, further progress in precursor purification and optimized fiber processing may lead to their application in less demanding structural applications such as automotive and industrial. Even in their current state, a lack of graphitic crystallinity results in a lower conductivity for the resulting CFs and makes them suitable for ultrahigh temperature insulative applications. Furthermore, the noncrystalline form of carbon obtained from bio‐based precursors clearly indicates a significant potential of carbon nanofibers, mats, and activated CFs in nonstructural applications that require a large specific surface area, such as electrochemical energy storage and purification. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43794.

Production of high strength carbon fibers from bio-derived precursors is of topical interest. Recently, we reported on dry-spinning of a partially acetylated softwood kraft lignin to produce carbon fibers with superior properties, but the thermo-oxidative stabilization step required a long time due to a slow heating rate needed to prevent the fibers from being heated too rapidly and sticking to each other. Here we report a rapid strategy of dual UV-thermoxidative stabilization (crosslinking) of dry-spun lignin fibers that significantly reduces the stabilization time. The fibers undergo reaction close to the surface such that they can be subsequently thermally stabilized at a rapid heating rate without fibers fusing together, which reduces the total stabilization time significantly from 40 to 4 h. Consequently, the glass transition temperature of UV irradiated fibers was about 15 °C higher than that of fibers without UV treatment. Stabilized fibers were successfully carbonized at 1000 °C and resulting carbon fibers displayed a tensile strength of 900 ± 100 MPa, which is amongst the highest reported for carbon fibers derived from softwood lignin-based precursors. These results establish that UV irradiation is a rapid step that can effectively shorten the total stabilization time for production of lignin-derived carbon fibers.