Enhancing Mechanical, Moisture Resistance, and Fire-retardant Properties of Nelumbo nucifera Fiber/Epoxy Nanocomposites with Zinc Oxide Nanoparticles

In recent years, an innovative material known as natural fiber-based nanocomposite has been developed. Furthermore, leveraging advancements in environmental nanotechnology, the eco-friendly composites exhibit potential for sustainable applications in lightweight structural materials and fire-resistant sectors, emphasizing reduced environmental impact and enhanced material efficiency. This investigation examined the influence of zinc oxide nanoparticles on moisture absorption, mechanical testing, fire retardant, and dynamic mechanical analysis of Nelumbo nucifera fiber (NNF) and epoxy (EP). The hand layup technique was implemented to create composite materials that comprised zinc oxide, NNF, and EP. The experiment revealed that the composites' modulus of elasticity (2117 MPa), tensile strength (48 MPa), and elongation at break (1.96%) were enhanced by increasing 12wt% zinc oxide (ZnO) nanoparticles. Conversely, the flexural strength and modulus of EP/NNF were 42 MPa and 2204 MPa, respectively. The modulus and flexural strength of EP/NNF/ZnO were 2814 MPa and 60 MPa, respectively, suggesting a 30.48% increase in bending strength. The swelling thickness and water absorption were substantially reduced (2.01% and 8.9%, respectively) as a result of the increased nanoparticle loading. To improve the dynamic mechanical properties (loss and storage modulus of 4.97 and 14.88 MPa) and performance (combustion rate of 18 mm/min, char residual of 31%) of composites, n-ZnO was incorporated. The X-ray diffraction (XRD) investigations showed that the 6 wt.% ZnO nanoparticles in the NNF fiber and EP samples still need to be more dispersed (2theta= 2.45 degrees, intercorrelation of 24.52%, and d-spacing of 40.24 nm). The chemical composition and distribution pattern greatly impact the toughness. The combustion process is impeded by the fabrication of char shields with a higher concentration of nano zinc oxide, necessitating elevated temperatures for degradation.