Biomimetic Biomass-Bsed Carbon Fibers: Effect of Covalent-Bnd Connection on Performance of Derived Carbon Fibers

The morphological collapse of pure biomass based carbon fibers is the main challenge restricting its development. Inspiration comes from nature that cellulose and lignin in natural trees are linked by covalent-bonds, leading to good extensibility and stability of wood. In this work, an effective strategy is presented to connect lignin and cellulose acetate by covalent-bond to obtain a novel carbon fiber precursor material. Isophorone diisocyanate was used as a chemical modifier to successfully connect lignin and cellulose acetate through a covalent-bond, which is formed by the urethane reaction of isocyanate group and hydroxyl group. With the introduction of covalent-bond connection, the precursor fibers exhibit a large molecular weight, uniform molecular weight distribution, excellent thermal stability, and good spinnability. After thermo-stabilization and carbonization, the pure biomass-based carbon fibers are successfully prepared. The results of SEM, BET, tensile test, and electrochemical properties test indicate that the covalent-bond connection effectively maintains morphology of fiber, which plays a key role for increasing the strength and the energy storage capacity of carbon fibers. The pure-biomass-based carbon fibers show promise for the production of high-quality, green, and cost reduced carbon fibers.