Multifaceted Characterization of Astragalus gummifer (Gum Tragacanth) Natural Fiber‐Reinforced Polymer Biocomposites: Mechanical, Dynamic, Thermal, and Acoustic Properties

ABSTRACT This study investigates the potential use of natural fibers derived from Astragalus gummifer (AG) as reinforcement in flame‐retardant polyester (FRP) composites. With rising demand for sustainable, eco‐friendly, and biodegradable materials, AG fibers offer a promising alternative, characterized by low density, thermal resistance, and lightness. Composites were fabricated using the hand lay‐up compression molding method, with FRP matrices incorporating AG fibers at 55%–75% volume fractions. The specimens were evaluated for density, porosity, water absorption, ultrasonic pulse velocity (UPV), compressive strength, thermal conductivity, acoustic absorption, and dynamic properties. The results showed that increasing fiber content reduced density and UPV, while porosity, water absorption, and compressive strength increased. Thermal conductivity ranged from 0.0656 to 0.1062 W/m·K, with porosity improving insulation performance. Acoustic tests revealed that specimens with lower resin content and higher porosity achieved excellent sound absorption at medium and high frequencies (SAC = 0.88 at 1600 Hz; SAC = 0.94 at 6300 Hz). Dynamic analysis indicated higher natural frequencies but lower damping capacity, confirming the trade‐off between stiffness and damping. These findings demonstrate that AG fiber‐reinforced composites are lightweight, sustainable materials with strong thermal and acoustic properties. Potential applications include energy‐efficient building insulation, as well as the automotive, aerospace, and defense industries where weight reduction and multifunctionality are required. However, high water absorption and weak fiber–matrix bonding, confirmed by SEM analysis, may limit long‐term durability, particularly in humid environments. Future research should focus on chemical modification, interfacial optimization, and aging tests to improve performance and broaden the applicability of these bio‐based composites.