Mechanical Performance Assessment and Streamlined Life‐Cycle Analysis of Random‐Waste Coir‐Fiber Metal Laminates

ABSTRACT This study explores sandwich structures based on the waste fiber metal laminate concept, integrating short random‐coir‐fiber composites with aluminium skins. The research investigates the combination of low‐cost aluminum alloy and natural fiber composites, focusing on three matrix systems: epoxy, polyester, and castor oil—a biobased, innovative alternative to conventional petroleum‐based polymers. Mechanical performance is evaluated through tensile, flexural, and interlaminar shear strength tests, supported by Classical Laminate and Laminated Beam Theories. A simplified life cycle assessment is conducted using the MECO matrix to assess environmental impact. To enhance skin‐core interfacial bonding, aluminum surfaces are treated with NaOH, followed by a pre‐primer application. Results reveal flexural modulus values ranging from 24.19 to 29.05 GPa and flexural strength between 89.47 and 103.07 MPa, demonstrating the competitive performance of these hybrid materials. A key contribution is the development of a strategy to improve interlaminar bonding, with NaOH‐treated epoxy‐CoRALs exhibiting a 15% increase in flexural strength compared to polyester‐CoRALs. Castor‐oil‐based CoRALs demonstrate superior specific mechanical properties and eco‐efficiency, requiring fewer processing steps and offering a sustainable alternative for lightweight structural applications. The MECO matrix analysis highlights the potential of castor‐oil CoRAL to achieve a win‐win scenario in eco‐mechanical performance, combining sustainability with competitive mechanical properties.