Water ageing effects on the mechanical properties of flax fibre fabric/polypropylene composite laminates

The increasing interest towards environmentally friendly materials for economic reasons and to comply with ever more stringent environmental requirements has allowed the flax fibres to gain an extraordinary interest in the development of new polymer composites. In fact, among plant fibres, the flax ones, given their low density, are characterised by specific mechanical parameters even higher than those of E-glass fibres. However, the application of composites reinforced with natural fibres remains confined to non-structural components. This matter is due to the requirement of important challenges resolution such as their intrinsic hydrophilicity and poor interfacial adhesion with hydrophobic polymer matrices, widely used for their easy processability, economy and lightness. In this context, this research has been focused on the flexural and low-velocity impact properties of polypropylene-based laminates, containing woven flax fibres and subjected to a pre-selected hygroscopic ageing protocol. The presence of a coupling agent, polypropylene-grafted-maleic anhydride, was considered too. Mechanical results, integrated with micrographic observations and visual inspections, provide useful details about the potential use of the studied materials already screened in the nautical field.