Recently, a project called LIBRE (lignin carbon Fiber Composites) was launched in Europe to extract lignin from paper pulp in the paper industry to make carbon fiber composites as a stable raw material. At present, most of the carbon fibers produced under technical conditions are made from polyacrylonitrile (pan), which is mainly refined from petroleum products. Lignin, as a kind of natural renewable material, meets the requirement of sustainable development, and has two advantages. First, the source is rich. Pulp as the waste of the paper industry just can be reused; second, the carbon content is high.
However, the goal of the LIBRE project is not only to find alternative raw materials, but also to find more economical and environmentally friendly fiber production processes. Instead of conventional heating, the project will use microwave or other high-frequency radiation to heat raw filaments to produce carbon fibers, giving them a more competitive price advantage.
The third goal of the project is to use plasma technology for fiber surface functionalization treatment to replace the traditional liquid chemical treatment method, more energy-saving and environmental protection. By this way, the adhesion between fiber and resin matrix can be strengthened, the strength of composite can be enhanced, and its lightweight application can be promoted.
As a participant in the project, the German Denkendorf Institute for Textile Chemistry and Fiber Chemistry, (ITCF), will lead the development of carbon fiber precursors. By adding other polymers and using the special melt spinning process developed by ITCF lignin is converted into a stable precursor and then carbonized. ITCF specifically marks a factory for testing and production. After the carbon fiber is delivered, it will be taken over by other participating companies for the production of final products which will be used in the field of automobiles and wind energy.