The research investigates the mechanical and thermal properties of hybrid date palm/glass fiber-reinforced composites with varying date palm fiber lengths. The study is motivated by the increasing interest in sustainable, eco-friendly composites incorporating natural fibers. For this purpose, treated date palm fibers (D2, D20, and UD fibers) were used as natural fiber reinforcement, and the composite samples were fabricated using hand lay-up combined with the vacuum-assisted hot press technique. Date palm/glass hybrid composites were characterized by various mechanical tests such as tensile, flexural, and impact testing. UD-glass exhibited a maximum tensile strength of 160.4 MPa, which is approximately 30.7% and 34.4% higher than those of D2-glass (122.7 MPa) and D20-glass (119.3 MPa), respectively. Furthermore, UD-glass indicated a maximum flexural strength of 646.9 MPa, representing an increase of 57.3% over D2-glass (411.4 MPa) and 114.5% over D20-glass (301.6 MPa). Additionally, UD-glass demonstrated the highest impact strength (402 J/m), which is 16.1% higher than D2-glass (346.2 J/m) and 6.8% more than D20-glass (376.4 J/m). The thermal properties of the hybrid composites were analyzed using thermogravimetric analysis (TGA). UD-glass exhibited the highest value of thermal stability at 372.6°C, indicating enhanced resistance to thermal degradation due to the unidirectional fiber arrangement. Results showed that UD fibers provided the best mechanical properties and highest resistance to thermal degradation. SEM analysis confirmed improved fiber-matrix interaction in composites with longer, aligned fibers.
