Abstract
Natural fibers from renewable resources present a sustainable and biodegradable alternative to synthetic reinforcements. This study explores the thermal and mechanical performance of Borassus husk fiber/epoxy composites, fabricated using a hand layup process with 5% NaOH alkali treatment at varying durations (0.5–2 h). Thermal and thermo-mechanical properties were assessed using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) followed by scanning electron microscopy (SEM) analysis, and outgassing tests. Results show that alkali treatment significantly improves the composites' thermal stability, indicated by increased char content (up to 8.11%) and higher integral process decomposition temperature (IPDT), with the 0.75-h treated sample reaching 525°C. The composites also demonstrated enhanced energy dissipation and stiffness compared to neat epoxy (NE) and other natural fiber-based composites. Glass transition temperature (Tg) decreased from 150°C (NE) to 126°C–137°C for treated samples, yet remained higher than those reported for other bio-fiber composites. The 0.75TBHFE sample exhibited the best balance between stiffness and damping, supported by improved phase angle and fiber–matrix adhesion observed in SEM analysis. Outgassing results showed an increase in total mass loss (0.11%–0.53%) compared to NE (0.26%), though still within acceptable limits for thermal stability. These findings highlight the potential of alkali-treated Borassus husk fiber/epoxy composites as high-performance, sustainable materials suitable for aerospace applications. Further research is recommended to address property variability in natural fibers and to develop efficient supply chains for large-scale industrial production.
