Regenerated Cellulose and Willow Lignin Blends as Potential Renewable Precursors for Carbon Fibers

We report on the extraction of lignin from willow and its use to manufacture cellulose-lignin fibers as potential precursors for the manufacture of carbon fibers. The lignin from willow was extracted using triethylammonium hydrogen sulfate [Et3NH][HSO4]. The lignin extracted by this process was characterized by ATR-IR and elemental analysis, which indicated a high carbon yield. 1-Ethyl-3-methylimidazolium acetate [C2C1im][OAc] was then used as a common solvent to dissolve cellulose and lignin to manufacture lignin-cellulose fiber blends. The Young’s modulus of a 75:25 lignin/cellulose fiber was found to be 3.0 ± 0.5 GPa, which increased to 5.9 ± 0.6 GPa for a 25:75 lignin/cellulose blend. From a characterization of the surface morphology, using scanning electron microscopy (SEM) and atomic force microscopy (AFM), it was observed that higher lignin content in the fiber blend increased the surface roughness. FT-IR analysis confirmed the presence of aromatic groups related to lignin in the obtained fibers fr...