Assessment of extended retted hemp fibres for composite reinforcement: fibre properties and adhesion with polyactide matrix

This study investigates the potential value of extended retted hemp fibres as a reinforcement of the polyactide (PLA) matrix. The hemp stems (Hungarian Tisza variety) underwent a particular retting consisting of harvesting them only 6 months after the end of cultivation, leaving them in a stand-up position for the whole autumn and winter seasons and part of spring in Estonia. Different hemp fibre surface treatments (water cleaning, sodium hydroxide in combination with silane) are conducted and their effects on the mechanical properties of the fibre and on the fibre adhesion with a PLA matrix are assessed.