Evaluation of Mechanical Properties of Alkaline-Treated Indigenous Fibers Reinforced Epoxy Composites

Abstract

This study evaluates the mechanical and thermal properties of epoxy composites reinforced with indigenous fibers—raffia, abaca, and coconut—treated with varying concentrations of sodium hydroxide (NaOH). Indigenous fibers are gaining attention as sustainable alternatives to synthetic reinforcements in composite materials due to their availability, cost-effectiveness, and environmental compatibility. The research investigates the impact of alkaline treatment on fiber properties, tensile strength, Young’s modulus, and thermal conductivity, with fiber loadings of one gram and two grams. The results demonstrate that alkaline treatment improves fiber-matrix adhesion, leading to enhanced mechanical and thermal properties. Raffia fiber composites achieved a maximum tensile strength of 9.93 MPa and a Young’s modulus of 9268 MPa at 3% NaOH concentration. Abaca composites exhibited superior mechanical performance, with a tensile strength of 18.13 MPa and Young’s modulus of 14,556 MPa under similar conditions. Coconut composites recorded a tensile strength of 14.32 MPa and Young’s modulus of 9431 MPa at 2% NaOH concentration. However, increasing fiber loading to 2 grams reduced tensile strength and thermal conductivity due to agglomeration and reduced matrix uniformity. Thermal conductivity improved with higher NaOH concentrations, peaking at 3% for all fiber types, consistent with literature on the benefits of alkali treatments. These findings align with studies by Patel et al. (2023) and Ramli et al. (2020), confirming that chemical treatments enhance fiber compatibility and overall composite performance. This research underscores the potential of indigenous fibers as viable reinforcements in sustainable composite materials, promoting advancements in eco-friendly engineering practice.