A peanut-hull-PLA based 3D printing filament with antimicrobial effect

Peanut hulls (Arachis hypogaea L.) are an abundant and stable biomass resource. In this study, peanut hull powder was incorporated into polylactic acid (PLA) to enhance its recyclability, and biodegradability while imparting the antimicrobial properties of the hull particles. The AHL particles were used as a reinforcing filler to produce composite filaments suitable for fused filament fabrication (FFF) 3D printing. A detailed, step-by-step procedure was developed for preparing the AHL particles, integrating them into PLA, and extruding high-quality filaments. The resulting filaments were evaluated based on their dimensional uniformity, mechanical strength, and elastic modulus, as well as physical properties including porosity, printability, wettability, and melt flow index. Unlike other biomass-based reinforcements in PLA, AHL particles preserved the filament's tensile strength and enhanced its elastic modulus. Component's 3D-printed from the PLA–AHL filaments retained antimicrobial activity and exhibited increased surface hardness. However, higher AHL mass fractions led to greater microvoid formation and rougher surfaces, rendering the material more prone to fracture and slightly reducing its fracture toughness.