Taweechai Amornsakchai

This study investigated the effects of adding cellulose nanofibers (CNF) to long pineapple leaf fiber (PALF)-reinforced epoxy composites. PALF content was fixed at 20%, while CNF content varied at 1%, 3%, and 5% of the epoxy matrix.  Adding small amounts of CNF had minimal impact on the flexibility and strength of the epoxy, but the impact strength with 1% CNF increased to about 115% of the pure epoxy. At higher CNF contents (3% and 5%), impact strength returned to the level of the pure epoxy. The fractured surface analysis showed a transition from a smooth to a rough surface. PALF-reinforced epoxy exhibited significantly improved flexibility and strength compared to the pure epoxy. The composite’s impact strength reached about 700% of the pure epoxy’s strength. Hybrid systems with both CNF and PALF showed minimal changes in flexibility and strength but exhibited a substantial improvement in impact strength. By using epoxy with 1% CNF, the impact strength increased to about 220% of the PALF-reinforced epoxy or 1520% of the pure epoxy. The remarkable improvement in impact strength resulted from the synergistic effect of CNF and PALF.