Mechanical and Vibro-Acoustic Properties of Bauhinia purpurea L Fiber‑Reinforced Polyester Composites

The reduction of environmental impact has been facilitated by stringent environmental regulations, the imperative to decrease greenhouse gas emissions, and the obligation to adhere to governmental laws for recycling and reuse. Natural fiber composites, which can rival synthetic fiber composites in performance, have been rapidly developed to meet the demand for lightweight structural materials. This research aims to investigate the mechanical, acoustical, and free vibration properties of biocomposites reinforced with Bauhinia purpurea L. biofiber in an unsaturated polyester matrix, considering various fiber weight percentages (5, 10, 15, 20, and 25wt.%) while maintaining a constant fiber length of 10 mm. The reinforced composite contains 20% fiber by weight offer better properties. The composites loaded with Bauhinia purpurea L. fiber exhibited exceptional characteristics, including a modulus of 3.72 GPa, tensile strength of 26.4 MPa, flexural strength of 68.92 MPa, impact strength of 9.55 kJ/m2, hardness of 85.22, and natural frequency of 52.84 Hz. The sound-absorbing properties were also improved, achieving a maximum noise reduction coefficient (NRC) of 0.492. The enhancements were primarily attributed to the reduced fiber length, leading to less stress concentration defects and enhanced interfacial adhesion between the fiber and matrix at the optimal content, as evidenced by Scanning Electron Microscope (SEM) analysis.