An eco-friendly acetylation treatment to improve flax/epoxy and flax/wood fibre/epoxy composites
A fibre reinforced composite (FRC) is a building material that consists of three elements: fibres, a polymer and the interface in between. FRCs are most often formulated with synthetic fibres (glass, carbon, Kevlar, and aluminum oxide) but can also be based on natural fibres such as linen or cellulose.
Acetylation is a common way to enhance interfacial adhesion between natural fibres and polymeric matrices (epoxy polymers herein) in composites. This work, within the Renewable Materials Research Centre, investigates the effect of a solvent-free and eco-friendly acetylation treatment, of short flax and kraft fibres. Two parameters are evaluated: the impregnation behavior and tensile properties of flax fibre/epoxy composites. Untreated and acetylated fibres have been used to prepare fibre mats, which were next studied for their morphology, their permeability to liquid epoxy, and their ability to adhere to the epoxy matrix after cure. The results show that acetylation enhances the roughness of flax fibres and improves fibre-matrix interaction, but reduces the permeability of the fibre mats and the intrinsic properties of fibres, thus leading to slightly lower composite modulus and strength. The proposed treatment is an interesting solvent-free environmentally friendly option to improve the affinity between natural fibres and polymeric matrices.
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