Flexural and Tensile Strength of Castor Oil-Based Polyurethane Composites Reinforced with Luffa Cylindrica Mats as a Sustainable Alternative to Oriented Strand Board

The main objective of this study was to develop and characterize a novel, eco-friendly composite material consisting of castor oil-based polyurethane (COPU) matrix reinforced with Luffa cylindrica mats hereafter referred to as luffa for potential use as structural panels and an alternative to oriented strand board (OSB). Mechanical properties were assessed through three point flexural testing, perpendicular to surface tensile testing. For benchmarking purposes, results were compared against commercial OSB panels. The luffa/COPU composites were fabricated via hand lay-up, incorporating luffa mats at 48 vol%, the maximum volume fraction permitted by the mold and available manufacturing resources. The incorporation of luffa mats significantly enhanced the mechanical performance of the COPU resin, with flexural strength and modulus of elasticity increasing by over 23 and 10 times, respectively. Other mechanical properties also more than doubled in comparison to the neat resin. Nevertheless, the notable mechanical improvements and overall performance of the composite support its viability for use in civil construction applications, particularly as a sustainable alternative to OSB. Key Words: Luffa cylindrica, composite materials, castor oil, polyurethane, natural fiber reinforcement, oriented strand board alternative.