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

Peanut hulls, also known as Arachis hypogaea L. particles (AHL), are an abundant biomass source with a long shelf life. In this study, we incorporate peanut hull powder into PLA polymer, imparting recyclability, biodegradability, and biocompatibility, along with the antimicrobial properties of AHL particles. In particular, we treat AHL particles as a reinforcement for PLA polymer to produce 3D printing filament compatible with the fused filament fabrication (FFF) 3D printing method. We provide a step-by-step method for preparing AHL particles, incorporating them into PLA, and ultimately forming high-quality filaments. We assess the quality of the filaments in terms of extruded dimensions, mechanical strength, and elastic modulus, along with physical properties such as porosity and melt flow index. We evaluate the printability and wettability of the filaments as well. Notably, and unlike other biomass-based reinforcements in PLA, AHL preserves the filament's strength and enhances its elastic modulus. 3D-printed components fabricated using our PLA-AHL filaments successfully retain their antimicrobial properties and exhibit increased overall hardness. However, this comes at the expense of forming more microvoids and a rougher surface, making the material more prone to fracture and leading to a slight reduction in fracture toughness with increasing AHL mass fraction.