Biodegradable composites filled with agro‐industrial waste and fertilizers for filament production and application in active manufacturing

Abstract One of the challenges to prioritizing a circular economy is the development of composites made with renewable polymer matrices and using agro‐industrial residues such as plant fibers. Aiming to follow the paths of a circular economy, this research aims to develop composites based on a blend of poly(butylene adipate‐co‐terephthalate) and polylactic acid filled with three plant residues: peanut shell, soybean shell, corn husk, and nitrogen–phosphorus–potassium fertilizer. For this, filaments of systems containing vegetable fiber (5 wt%) and fertilizer (3 wt%) were processed in a single‐screw extruder. The filaments were characterized by Fourier transfer infrared spectroscopy (FTIR), thermogravimetry, differential scanning calorimetry, surface morphological analysis, and mechanical behavior. The FTIR indicated changes in the blend's characteristic bands, suggesting an interaction between the polymer matrix and the fillers. The fertilizer altered the systems' thermal properties and thermal stability. The fertilizer significantly affected (p < 0.05) the mechanical properties in a particular way in each system. Finally, the presence of surface agglomerates were confirmed in the morphological analysis. Additionally, these composites can be applied as raw materials to produce filaments for active manufacturing in the agricultural sector, adding value to the available natural residues while adhering to a circular economy. Highlights Poly(butylene adipate co‐terephthalate) (PBAT)/poly(lactic acid) (PLA) composites filaments were produced using agro‐industrial waste; Mineral compound fertilizer was incorporated into PBAT/PLA composites; Agro‐industrial waste in composites adds value to filler and promotes the circular economy.