Abstract

This study examines the impact of elevated temperatures on the mechanical properties of Borassus husk fibre-reinforced epoxy composites, focusing on the effects of alkali treatment (5% NaOH) on the fibres with varying treatment durations. Dynamic Mechanical Analysis (DMA) was conducted according to ASTM 5418-01 standards. The results showed that both untreated and alkali-treated fibres increased the storage modulus of the composites. The loss modulus significantly increased only for the alkali-treated composites, where the 1-hr treated fibre composite show the highest value. The glass transition temperature (Tg) of neat epoxy was 82 °C, which increased to 89 °C for composites with 0.75-hr treated fibres but decreased to 79 °C for untreated fibres. The tan δ (damping factor) also increased significantly with alkali treatment, with the highest value (1.2) observed for the 0.75-hr treated fibre composite, 33% higher than neat epoxy (0.9). Cole-Cole plots revealed improved resin-fibre adhesion for composites incorporated with 0.75 and 1 hour treated husk fibre. Phase angle data confirmed enhanced energy dissipation and viscoelastic properties in the treated fibre/epoxy composites. Furthermore, the total mass loss (TML) was the lowest for the 0.75-hr treated fibre/epoxy composite (0.4%), about 33% lower than neat epoxy, indicating better thermo-mechanical stability. Overall, alkali-treated Borassus husk fibre composites demonstrated superior mechanical stiffness, damping capacity and thermal stability compared to neat epoxy, making them promising materials for applications in aerospace and automotive industries, where performance, vibration reduction and sustainability are essential.