Eco-friendly hybrid epoxy composites reinforced with snake grass fiber and dual agro-waste fillers for enhanced mechanical and acoustic performance

This study examined the mechanical, acoustic, and microstructural performance of epoxy composites reinforced with Snake Grass Fiber (SGF) and hybrid agro-waste fillers—Tamarind Seed Powder (TSP) and Wood Apple Shell Powder (WASP). Composites were fabricated by compression molding with a constant SGF content of 30 wt% and varying hybrid filler contents (5 to 15 wt%). Mechanical properties including tensile, flexural, compressive, impact strength, hardness, and water absorption were evaluated alongside sound absorption behavior. The incorporation of hybrid fillers significantly improved mechanical strength, surface hardness, and dimensional stability while reducing moisture uptake compared to SGF-only composites. The optimized hybrid composition exhibited superior properties, achieving tensile, flexural, compressive, and impact strengths of 58 MPa, 87 MPa, 70 MPa, and 8.98 J, respectively, with a hardness of 84 Shore D and reduced water absorption of 23%. Acoustic analysis revealed enhanced sound absorption, with a maximum absorption coefficient of 0.24 at an optimal filler-to-fiber ratio, attributed to synergy between fibrous reinforcement and porous fillers. SEM analysis confirmed uniform filler dispersion, improved interfacial bonding, and reduced voids, supporting the observed mechanical and acoustic enhancements. SGF-based hybrid agro-waste composites offer improved structural and sound-absorbing performance, making them suitable for sustainable automotive, construction, and acoustic insulation applications.