Mechanical properties of tough plasma treated flax fibre thermoplastic composites

Natural fibres (NF) have shown to be a suitable alternative to glass fibres as reinforcing material in polymer composites since they offer similar specific strength and stiffness. Thus, those composites may be readily used in the automotive, sport and leisure. However, most of today's natural fibre applications are based on discontinuous fibre architectures, underrunning the performance of continuous synthetic fibre composites. Flax fibres show a great potential to be used as continuous reinforcing fibres in thermoplastic matrix composites. The use of high performance engineering polymers and the application of preceding plasma-based fibre surface treatments may further enhance the mechanical properties, making flax fibre thermoplastic composites an environmentally friendly alternative. We investigated the mechanical behaviour of pure flax fibres, introduced an engineering polymer as matrix system, compared this material to commonly used matrices such as epoxy or polypropylene and studied the effect of two different plasma treatments on the mechanical performance of natural fibre composites (NFC). The influence of the plasma methods was found through composite failure testing. Results have shown, that composites with plasma treated fibres and engineering polymers along with a high fibre volume content offer a great potential as environmentally sustainable substitutes for synthetic composites in many applications.