Mechanical and moisture behaviour of abaca and sisal fibre-reinforced epoxy composites

The shift towards sustainable practices has increased the focus on natural materials due to their biodegradability and recyclability. This study explores the tensile, flexural, and water absorption properties of abaca/epoxy, sisal/epoxy, and abaca–sisal/epoxy hybrid composites, with fibres oriented at a 45° angle. These composites were fabricated and tested according to ASTM standards to evaluate mechanical properties and moisture resistance. The results indicated that abaca/epoxy composites exhibited the highest tensile and flexural strength, making them suitable for load-bearing applications. In contrast, sisal/epoxy composites demonstrated greater flexibility and better moisture resistance. The abaca–sisal hybrid composite, however, showed lower performance in both mechanical strength and water absorption, mainly due to poor fibre–matrix bonding and distribution. The hybrid’s increased moisture absorption further highlights the challenges of integrating different fibres within a single matrix. The study concludes that abaca/epoxy composites are best suited for strength-focused applications, while sisal/epoxy composites are more appropriate for moisture-sensitive environments. The hybrid composite requires further optimisation to improve structural integrity and water resistance.