Cellulose-lignin composite fibres as precursors for carbon fibres. Part 1 -Manufacturing and properties of precursor fibres Mikaela Trogen (Conceptualization) (Investigation) (Formal analysis) (Visualization) (Writing -original draft), Nguyen-Duc Le (Resources) (Writing -review and editing), Daisuke Sawada (Investigation) (Formal analysis) (Visualization) (Writing -review and editing), Chamseddine Guizani (Formal analysis) (Writing -review and editing), Tainise Vergara Lourençon (Investigation) (Formal analysis) (Writing -review and editing), Leena Pitkänen (Investigation) (Formal analysis) (Writing -review and editing), Herbert Sixta (Resources) (Supervision), Riddhi Shah (Investigation) (Writingreview and editing), Hugh O'Neill (Resources) (Writing -review and editing), Mikhail Balakshin (Resources) (Writing -review and editing), Nolene Byrne (Resources) (Supervision) (Writing -review and editing), Michael Hummel (Supervision) (Funding acquisition) (Conceptualization) (Resources) (Writing -review and editing)

The increasing demand for a low-cost and renewable carbon fibre precursor has driven the focus on bio-based precursors. Cellulose-lignin composite fibres are a new approach toward this direction. The combination of cellulose and lignin into a composite fibre could solve some of the current limitations for pure cellulose and lignin fibres. This study investigated the treatment of the composite fibres with boric acid with focus on carbon yield, stabilisation rate and fibre fusion, which is a typical defect in carbon fibre production. The influence of boric acid on the mechanism of stabilisation was studied. The stabilisation time was reduced by 25% through treatment with the reduction of fibre fusion, while the carbon yield increased significantly in comparison to the untreated fibres.

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