Characterization of conch shell powder reinforced PLA composite filaments for additive manufacturing applications

In recent years, PLA-based composite filaments have gained significant importance in additive manufacturing due to their biodegradability, ease of processing, and potential for improved functional properties. Although natural fillers such as wood, eggshell, and various shell powders have been explored, the potential of conch shell powder, an abundant CaCO 3 -rich waste remains largely unexamined in current research trends. To address this gap, this study systematically characterizes PLA/composite filaments incorporating conch shell powder at 0, 2, 4, 6, and 8 wt% to evaluate the effects of filler loading on thermal stability, mechanical behavior, morphology, and printability. The study involves filament extrusion, followed by comprehensive characterization through XRD, FTIR, DSC, TGA, melt flow index testing, tensile testing, and SEM analysis. Results reveal that 4 wt% PLA/conch shell composites exhibited improved tensile modulus. Notably, all compositions except 8 wt% maintained suitable melt flow properties for FDM, confirming their printability. These findings provide a comprehensive overview of the material behavior of FDM-based PLA/conch shell composites. Together, they form a systematic characterization of how conch shell powder influences the properties of PLA. Thus, this work demonstrates the potential of the developed bio-based filaments as suitable feedstock for producing customized lightweight components.