Investigation on the thermal, mechanical, and morphological characterization of peepal fiber-reinforced epoxy composites enhanced with micro-particulate ziziphus mauritiana seed powder

ABSTRACT Natural fibers are gaining significant research attention due to their ecological, renewable, and environmentally friendly nature, making them attractive alternatives to synthetic reinforcements. This experimental study investigates the thermo-mechanical behavior of Peepal fiber (PF) reinforced epoxy composites modified with Ziziphus mauritiana seed powder (ZMSP). Hybrid composites were fabricated by maintaining a fixed fiber weight fraction of 40% PF, while varying the particle content at 3, 6, 9, and 12 wt%. Prior to incorporation, the particles were chemically treated with 5% NaOH and characterized using FTIR, XRD, and TGA analyses. The treatment increased crystallinity index, enhanced thermal stability, and promoted better interfacial adhesion with the matrix. Mechanical tests revealed that composites with 3 wt% filler displayed the highest impact strength, whereas 9 wt% filler exhibited optimum tensile, compressive, flexural, hardness, and fracture toughness properties. Thermogravimetric analysis confirmed enhanced thermal resistance, while water absorption and biodegradability increased with particle loading. SEM micrographs illustrated improved fiber–matrix interaction and reduced void formation at optimal filler content. The combined improvements in strength, toughness, and stability demonstrate that PF–ZMSP hybrid composites can serve as sustainable, cost-effective, and lightweight materials suitable for moderate load-bearing applications in automotive, structural, and industrial sectors.