Pulped Phormium tenax leaf fibres as reinforcement for epoxy composites

Leaf fibres from Phormium tenax (harakeke, New Zealand flax) were pulped at 170 °C with NaOH and anthraquinone. The pulp was wet laid to form mats, which were used to reinforce epoxy composites. The flexural modulus was almost as high as that measured for epoxy reinforced with glass chopped strand mat at the same weight fraction. The flexural strength was two-thirds that of the glass-reinforced composite. Failure was abrupt. SEM images showed torn fragments of fibre cell walls protruding from the fracture surface, indicating strong interfacial bonding. Good mechanical performance was attributed to the rarity of kink bands in the individual fibre cells, along with wrinkled cell-wall surfaces that enhanced the area of the fibre–matrix interface.