Assessment of the feasibility of vegetable-based polyurethane composites reinforced with long coconut fibers impregnated with clove oil via supercritical CO 2 for prosthetic applications

Medical prostheses are traditionally made from non-renewable, high-cost materials. This study explored biodegradable polyurethane (PU) composites reinforced with coconut fibers and incorporated with clove oil (CEO) as an antimicrobial agent. PU composites, with natural (NCF) or mercerized (MCF) coconut fibers, were manually prepared and functionalized via surface coating and scCO 2 impregnation of the fibers with CEO. Characterization of the fibers by FTIR, SEM, and XRD confirmed expected results, with mercerization enhancing fiber-PU interaction. PU/NCF and PU/MCF composites demonstrated significant improvements in mechanical properties, specially in tensile strength (210%–460%) and impact resistance (280%–520%); a 35% reduction in density, and a 40% rise in water absorption compared to PU. ScCO 2 impregnation (20 or 30 MPa, 45°C, 3 h) resulted in impregnation efficiencies of 7.5% to 12.1% for MCF and NCF, with NCF exhibiting higher efficiency due to lower crystallinity. The CEO release was partial after 45 days, and the antimicrobial effect against Escherichia coli was promising. These results, along with the findings from computational simulations, highlight the potential of biobased PU composites with coconut fibers for prosthetic applications.