Fluorination of flax fibers for improving the interfacial compatibility of eco-composites

International audience; Because of their specific properties, vegetal fibers are increasingly used as sustainable polymer reinforcementsfor eco-composites. Nevertheless, their polar character hinders them from being used more frequently at in-dustrial scale due to their incompatibility with mostly dispersive polymers (the cheapest and most commonones). In this study, direct fluorination treatment was carried out to covalently graft fluorine atom at the outmostsurface of flax fibers. Such a grafting has been proved by FT-IR, 19F NMR and XPS spectroscopies, and thesecharacterizations allowed to understand chemical change due to the treatment. This chemical modificationinduced an augmentation of the dispersive character of flax fibers, by significantly lowering the polar componentof surface energy without significant change of the dispersive component. Young’s modulus was also maintained.Thereby, treated fibers become perfectly compatible with hydrophobic polymer, and an improvement in themechanical performance of the resulting composite is expected according to the literature.