Mechanical Performance Evaluation of Natural Composites Recycled Hemp Rice Bag Reinforced with and without Silicon Carbide Particles

Significant progress has been made in the development of natural fiber-reinforced composite materials, owing to their potential to enhance mechanical properties while offering a greener and more sustainable alternative to traditional materials. These materials combine superior ecological benefits with enhanced mechanical performance. This study examines how recycled hemp fiber bags, including recycled hemp fibers obtained from rice hemp fiber bags, affect the mechanical characteristics of unreinforced and reinforced composites. Four composite systems were fabricated and tested: (1) HFR (randomly chipped recycled hemp fiber bags–epoxy composite), (2) HFB (continuous recycled hemp fiber bag–epoxy composite), (3) HFR SiC (randomly chipped recycled hemp fiber reinforced with silicon carbide particles), and (4) HFB SiC (continuous recycled hemp fiber bag reinforced with silicon carbide particles). Hardness, tensile strength, and impact resistance were evaluated and analyzed. Each composite group was tested using three replicates, and all mechanical results are presented as Mean ± Standard Deviation. The results revealed that adding silicon carbide significantly improved the mechanical performance. The HFB SiC composite achieved the highest tensile strength of 20.9 MPa, Vickers hardness of 350 HV, and impact resistance 20 kJ/m2, compared to unreinforced composites (HFB: 18 MPa; 53 HV; 14 kJ/m2). Overall, composites reinforced with silicon carbide exhibited superior hardness, strength, and impact resistance compared to those without reinforcement. Among all, the HFB SiC composite was identified as the optimal and most promising material for eco-friendly structural and semi-structural applications requiring high strength, stiffness, and toughness