Biobased carbon fibers - how to avoid fibers sticking together?

Carbon fibers from lignin-cellulose

Using carbon fibers as reinforcement in composites provide a lightweight material that can replace steel, aluminium or glass fibers in many applications, e.g. in the transport sector or in the turbine blades for wind mills. Today's carbon fibers are unfortuntately too expensive for many products and are also made from fossil-based polymers. Lignin has for a long time been considered to be an attractive candidate as raw material for carbon fibers, since it not only comes from a renewable resource and has a high carbon content, but can also be produced as a byproduct from pulp mills. However, a practical problem is that precursor fibers containing lignin easily stick together, or fuses, which causes further problems in the subsequent processing steps. For example, it can increase the risk of uneven tension distribution in the fiber bundle during carbon fiber production, which is devastating from a production point of view as it increases the risk of fiber breakage and thus stoppage of production.

Aim and vision of the project

The long-term vision is to develop resource efficient and sustainable forest-based carbon fibers as a complement to the expensive petroleum-based carbon fibers on the market today.

After finalization of the project, the objectives are:

• Determined fundamental causes to why the fibers stick together by investigating thermomechanical (drying/pressing) and chemical methods (washing/spin finish) with potential to reduce the problems.
• Developed at least one solution that satisfactorly solves the problem
• Evaluated the solution with respect to sustainability, process and cost for up-scaling