Abstract text: Flax is an economically important plant for seed-oil and fibre productions. Flax fibres are located in the phloem tissues of the plant stem and are composed of crystalline cellulose elementary microfibrils embedded in hemicelluloses, pectin and lignin (middle lamella). These fibres are widely used in the textile and composite industries after processes, such as retting, scutching, hackling and degumming/bleaching aiming at isolating white cellulose elementary fibres before yarn spinning. 
In the context of the UPWEARS European project¹, we revisited the degumming/bleaching process (part of yarn production) using Deep Eutectic Solvents (DES) to replace the classical polluting oxidative treatments that introduce default to the fibres. Indeed, these solvents offer the valuable advantage of being recyclable. Moreover, adjusting the hydrogen bond acceptor and hydrogen bond donor components of DES allows them to selectively affect the different binding components of elementary fibres.
This study presents a multi-step process combining DES treatment to achieve degumming and partial bleaching of flax rovings, as demonstrated by FTIR, chromametric, and mechanical characterizations. The treated rovings showed excellent yarn spinnability, highlighting the potential of this approach for more sustainable processing of plant-based fibres.

1: https://www.upwears.eu/