Mechanical and falling weight impact properties of unidirectional phormium fibre/epoxy laminates

The falling weight impact properties of composites obtained by introducing 16 wt% of phormium tenax fibres extracted with two different methods i.e., either manually or by paddocking and scutching and in both cases chemically treated with a 1% solution of sodium hydroxide, have been investigated. The effect of the two extraction methods on fibre characteristics is compared by the tensile properties of the fibres and the flexural properties, fracture modes and hysteresis cycles parameters (impact energy partition, linear stiffness and normalised penetration energy) of final laminates. Laminates obtained using paddocked and scutched fibres are clearly superior to those manufactured using the manually extracted fibres: this is due to the more effective fibre impregnation in the former case than in the latter, which results in an improved dissipation of energy during the damping phase of the impact event. It is noteworthy, however, that the low volume of fibres introduced in the laminate with the manufacturing method adopted does not allow obtaining properties comparable with other semi-structural plant fibre composites, such as e.g., hemp fibre reinforced laminates