An acetylated softwood kraft lignin was dry-spun into precursor fibers and successfully
processed into carbon fibers with a tensile strength exceeding most values reported in prior
studies on lignin-based carbon fibers. Limited acetylation of lignin hydroxyl groups enabled
dry-spinning of the precursor using acetone (solvent) followed by thermo-oxidative stabilization.
Resulting carbon fibers (7 lm diameter) displayed a tensile modulus, strength,
and strain-to-failure values of 52 ± 2 GPa, 1.04 ± 0.10 GPa, and 2.0 ± 0.2%, respectively.
Because of solvent diffusion during dry-spinning, fibers displayed a crenulated surface that
can provide a larger specific interfacial area for enhanced fiber/matrix bonding in composite
applications.