Enhancing Thermal and Dynamic Mechanical Properties of Alkali-Treated Borassus Husk Fibre Reinforced High-Heat Resistant Epoxy Composites

Natural fibers from renewable resources offer a sustainable as well as biodegradable alternative to synthetic reinforcements in polymer composites. This study investigates the thermal and mechanical behavior of Borassus husk fiber-reinforced epoxy composites, fabricated via the hand layup method. The fibers were alkali-treated with 5% sodium hydroxide (NaOH) for varying durations (0.5 to 2 h) to improve interfacial bonding. Thermal and dynamic mechanical properties were analyzed using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Alkali treatment enhanced thermal stability, as indicated by increased char residue (up to 9.43%) and higher integral process decomposition temperatures (IPDT), with the 1-h treated sample achieving the highest IPDT of 554°C. Compared to neat epoxy and other natural fiber composites, Borassus fiber composites exhibited superior energy dissipation, stiffness, and mechanical strength. Although the glass transition temperature (Tg) decreased from 149°C in neat epoxy to between 122°C and 140°C in treated composites, the values remained competitive. The 0.75TBHFE demonstrated the best overall performance, with optimal storage modulus, improved damping and minimal mass loss. These findings underscore the potential of alkali-treated Borassus husk fiber/epoxy composites for high-performance applications, such as aerospace, while promoting environmental sustainability and supporting net-zero carbon emission goals.