Role of interface formation versus fibres properties in the mechanical behaviour of bio-based composites manufactured by Liquid Composite Molding processes

The aim of this work was to study the effect of free surface energy modification of flax fibres by a thermal treatment on the mechanical behaviour of bio-based composites. It has been proved that this modification enhances the wettability of flax fibres by liquid epoxy resin and results in a lower porosity amount in composites. Tests to evaluate mechanical properties of elementary fibres, yarns and composites have been performed. The main outcome of this multiscale study, even if elementary fibres and yarns have been embrittled and interface properties have been lowered after thermal treatment, is that the mechanical behaviour of composites manufactured by Liquid Composite Molding (LCM) is better with treated fibres.