Biocomposites made of natural fibers and biomass-based thermoset resins aim at playing a significant role in the fields of construction, automotive, and aeronautics thanks to their light weight property and absence of petro-chemical origins. Furan resin, produced from the hemicellulosic part of agricultural wastes, reinforced by flax fibers is a promising biocomposite as it should combine the intrinsic good mechanical properties of the natural fibers with the excellent fire performance of the bio-based resin. The interfacial strength between the fibers and the resin also determines to a large extent the final properties of the materials, i.e. the compatibility between both constituents must be good to guarantee an homogeneous impregnation of the fibers. To predict such compatibility, surface energetic components of the fiber and the cured resin are traditionally assessed and compared. However, such method is subjected to criticism as during the processing of the composite, the resin, in liquid and not in solid state, first impregnates the fibers and only later on cures. As the chemical nature of the resin is modified during curing, different surface energetic components between the uncured and cured resins are expected. This hypothesis was checked for a furan water-based resin which shows a modification of its Lifshitz-Van der Waals component as well as its acidic and basic components. This work demonstrates the need for a better characterization of reactive resins in order to provide a more reliable prediction of their compatibility with fibers which should eventually lead to better biocomposites.
david.seveno@mtm.kuleuven.be
