Next-generation automotive materials: Performance-driven yucca fiber reinforced PA11 bio-composites

Developing sustainable engineering materials requires systems that merge renewable origin, mechanical resilience, thermal stability, and industrial scalability. In this study, bio-based polyamide 11 (PA11) was reinforced with yucca fibers extracted via two eco-designed routes, traditional (YT) and water retting (YWR), to create next-generation bio-composites processed through injection molding. The incorporation of yucca fibers significantly enhanced the mechanical properties of PA11. Traditionally extracted fiber-reinforced composite (PA11-YT5) enhanced tensile (35.02 MPa) and flexural strengths (43.08 MPa) compared to 34.83 MPa and 41.81 MPa for neat PA11. Meanwhile, the water-retted composites (PA11-YWR5) exhibited accepted strength (34.75 MPa in tensile, and 41.84 MPa in flexural) with greater impact resistance and improved thermal stability. Enhancing the Heat Deflection Temperature (HDT) is key for enabling bio-composites to operate in thermally demanding applications. Here, yucca reinforcement markedly improved thermal resistance: the neat matrix showed an HDT of 72.25 °C, while fiber incorporation increased it by +52% (PA11-YT5%) and + 55% (PA11-YWR5%). After hygrothermal aging (37 °C, 85% RH, 30 days), both systems retained over 98% of their initial strength in tensile, demonstrating high environmental durability. Life cycle assessment (i.e., LCA) confirmed a lower carbon footprint (≈1.27 kg CO₂ eq./kg) and reduced processing energy relative to neat PA11. The results of this study highlight yucca fibers as a compelling renewable alternative to widely used natural fibers, providing consistent mechanical reinforcement and notable thermal stability. Combined with their environmental advantages, these characteristics position yucca fibers as attractive candidates for sustainable automotive components and lightweight structural applications.