Green composites based on biodegradable polymers and anchovy (Engraulis Encrasicolus) waste suitable for 3D printing applications

Every day large amounts of fish waste are produced and grossly discarded in markets around the world causing environmental and hygiene issue. The use of these scraps for the production of materials with higher added value can definitely contributed to solve this problem. In this work, 10% and 20% of anchovy fishbone powder (EE), obtained by market waste, were microbiological and mechanical tested and subsequently added to polylactic acid (PLA) and to a commercial blend of biodegradable co-polyesters (Mater-Bi®). Rheological characterization suggests the potential printability of all prepared composites filaments. 10% EE filled composites showed outstanding printability. Morphological analysis confirmed the obtainment of good dispersion of the filler and the excellent adhesion of EE particles with the matrices in the composites filament and in 10% printed samples. The filler effectively acted as reinforcement in flexural and impact test: for MB and PLA, the addition of EE leads to an increase of flexural modulus of about 23% and 32% respectively. In tensile test both composites turn out to be influenced by the oil contained in the filler that act as plasticizer: the elongation at break of MB increased by 364% when 10% of EE was added. The experimental data obtained by tensile tests showed an opposites behavior than those predicted by Halpin–Tsai model, presumably due to the presence of residual fish oil acting as internal slipping agent.