Sustainable hybrid composites from flax, vetiver, and <i>Luffa cylindrica</i>: Acoustic and structural performance

Abstract Sustainable, eco‐friendly composites have always been of great interest due to increasing environmental awareness. In this regard, there is a continuous demand for alternative sustainable materials with enhanced performance. This study focuses on the development of sustainable hybrid composites using flax fibers, vetiver root fibers, and Luffa cylindrica fillers. Composites were fabricated using varied fiber loading ratios and evaluated for tensile, flexural, impact, interlaminar shear strengths, and sound absorption capabilities. Pure flax composites (FV) exhibited the highest tensile strength (40.2 MPa), whereas the hybrid containing two flax layers and 51 g of vetiver fiber (FVL3) achieved the best acoustic absorption, attenuating up to 65% of incident sound. Morphological analysis via SEM revealed that optimized fiber–matrix bonding and a well‐distributed porous network in FVL3 contributed to its superior sound absorption. Although vetiver‐rich composites showed improved impact behavior, excessive vetiver content led to diminished tensile properties due to lower cellulose levels and reduced fiber–matrix adhesion. The results confirm that balancing flax and vetiver inclusions can tailor mechanical and acoustic performance. Consequently, FVL3 is recommended for noise mitigation applications, such as acoustic wall panels, where moderate mechanical strength and high sound absorption are essential. Meanwhile, pure flax‐based laminates (FV) can be prioritized in load‐bearing scenarios requiring higher tensile strength. Therefore, the findings underscore the potential of flax–vetiver–luffa (FVL) hybrids as sustainable alternatives for structural and noise‐control applications, offering a route to environmentally responsible composite design without sacrificing performance. Highlights Eco‐friendly hybrid composites developed using flax, vetiver, and luffa. Alkali treatment improves fiber‐matrix bonding and composite performance. Flax composites achieve the highest tensile strength of 40.2 MPa. FVL3 composite absorbs 59% of sound, ideal for acoustic applications. Sustainable, biodegradable materials reduce environmental impact effectively.