High Lignin Content Carbon Fiber Precursors Wet-Spun from Low-Cost Ionic Liquid Water Mixtures

Lignin is an abundant biopolymer present in wood biomass and a promising renewable precursor for carbon materials. Lignin-derived fibers (CFs) are attractive target sustainable composite applications, due to the global scope achieving energy efficiencies, if cost-effective manufacturing technologies can be developed. Here, mixture of low-cost (<$1/kg) ionic liquid (IL), N,N-dimethylbutylammonium hydrogen sulfate, [DMBA][HSO4], water shown effective solvent continuous wet-spinning high lignin content fibers. Homogeneous solutions formed unmodified lignins (Kraft or ionoSolv) partially hydrolyzed poly(vinyl alcohol) were prepared aqueous IL mixtures (60:40 wt/wt % [DMBA][HSO4]:H2O) spun into with circular cross-sections using 1 M Na2SO4 pure as coagulant. The 75–90% had tensile strengths 25–50 MPa moduli 3–5 GPa. After oxidative stabilization carbonization at 1000 °C, yield up 40% was achieved, 450 40 GPa, respectively. With further process optimization, new spinning approach has promise scalable provide biobased CFs that environmentally benign.