This study addresses the limited understanding of how biomass-derived nano-fillers influence the fatigue, creep and machinability of hybrid fiber-reinforced epoxy composites. Epoxy-based laminates with a Pineapple-Pine screw/Glass/Pineapple-Pine screw/Glass fiber (PS/G/PS/G)stacking sequence were fabricated and reinforced with biochar and biosilica fillers to elucidate their comparative structure-property relationships. The findings demonstrate that biosilica significantly enhances mechanical durability and drilling stability compared to biochar, primarily due to its finer particle size, higher stiffness, and stronger interfacial bonding with the epoxy matrix. The formation of silanol-mediated interfacial networks restricts crack propagation under cyclic loading and improves resistance to time-dependent deformation. However, the hydrophilic nature of biosilica increases moisture uptake, highlighting a trade-off between mechanical performance and environmental sensitivity. Drilling investigations reveal that biosilica-reinforced composites exhibit improved dimensional stability and reduced damage during machining, attributed to the rigid filler–matrix microstructure. Microstructural analysis confirms enhanced filler dispersion and fiber–matrix adhesion in biosilica-filled composites, leading to superior structural integrity. This work provides mechanistic insight into the role of sustainable nano-fillers in hybrid composites and offers practical guidance for designing bio-based materials with improved mechanical reliability and machinability for structural and engineering applications.
T et al. (2026) studied this question.