Sustainable PLA composite filaments reinforced with bio-waste derived prawn shell particles for additive manufacturing

The present study investigates the development and characterization of sustainable poly(lactic acid) (PLA) composite filaments reinforced with bio-waste derived prawn shell particles (PSP) for fused deposition modeling (FDM) applications. PLA/PSP composite filaments containing 5–20 wt% PSP were fabricated using a multi-zone twin-screw extrusion process, and their dimensional stability, surface morphology, thermal behavior, and mechanical performance were systematically evaluated. The incorporation of PSP significantly influenced the extrusion quality and structure–property relationship of the developed filaments. Among the investigated compositions, the 15 wt% PSP composite exhibited the best overall performance, achieving a tensile strength of 46.2 MPa with improved surface uniformity due to enhanced filler dispersion and interfacial adhesion. Thermal analysis revealed that the 10 wt% PSP composite exhibited superior thermal stability with an onset degradation temperature of 372°C, while higher PSP loadings promoted increased char formation because of the mineral-rich nature of the prawn shell particles. SEM observations further confirmed homogeneous particle distribution and reduced interfacial defects at the optimum filler loading. Overall, the study demonstrates the potential of prawn shell waste as a sustainable bio-reinforcement for developing high-performance biodegradable PLA filaments for additive manufacturing applications.