Meddah, MostefaAmroune, SalahRokbi, MansourBelaadi, AhmedBouaziz, NourelimaneAchour, SaberAbdullah, Mahmood M. SAlLohedan, Hamad A.Al-Khawlani, AmarMukalazi, Herbert2026-03-302026-03-302026-03-26Meddah, M. et al. (2026). Comparative Analysis of Polyester Composites Reinforced with Local Plant Fibers: Stipa tenacissima Vs. Agave americana. Journal of Natural Fibers, 23(1), 2646163.https://doi.org/10.1080/15440478.2026.2646163https://hdl.handle.net/20.500.12504/280720 p.This work presents a comparative investigation of unsaturated polyester composites reinforced with two local Algerian lignocellulosic fibers: Stipa Tenacissima and Agave americana. These fibers were harvested, water-retted, and subsequently characterized using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). Singlefiber tensile testing, supported by Weibull statistical analysis, showed that Stipa Tenacissima fibers exhibit a higher Young’s modulus (~15.5 GPa) and lower elongation at break, whereas Agave fibers display lower stiffness (~6.7 GPa) but significantly greater ductility. Two unidirectional composites, unsaturated polyester/ Stipa Tenacissima and unsaturated polyester/ Agave Americana, containing each approximately 25 wt% fiber were fabricated using the vacuum-bagging process and cured at 70 °C for 2 h. Mechanical testing revealed substantial improvements compared to neat polyester. Stipa Tenacissima fiber composites achieved an increase of about 120% in tensile modulus and nearly 110% in flexural modulus. In contrast, Agave Americana fiber composites exhibited lower stiffness but superior strain-to-failure and toughness, with an enhancement of ~95% in flexural strength. Overall, the results confirm that both Stipa Tenacissima and Agave Americana are effective reinforcements for polymeric matrices: Stipa Tenacissima fibers primarily improve stiffness and strength, while Agave fibers enhance ductility and energy-absorption capability.enStipa tenacissimaAgave americanaNatural fiber compositesPolyester resinTensile and flexural propertiesWeibull statisticsArticle