Development and Optimization of PLA-MoS ₂ /SiC Filaments for Sustainable 3D Printing Applications

The development of high-performance and sustainable filaments for fused filament fabrication (FFF) remains constrained by the moderate mechanical strength and thermal stability of neat polylactic acid (PLA). In this study, a dual-reinforced PLA–MoS 2 /SiC composite filament was developed and statistically optimized for functional and rapid tooling applications. A Taguchi L9 orthogonal array was employed to investigate the influence of filler composition, extrusion temperature (150–160 °C), and screw speed (3–7 rpm) on tensile performance. The optimized composition (98–0.5–1.5 wt.% PLA–MoS 2 –SiC), processed at 155 °C and 3 rpm, exhibited a peak tensile strength of 37.77 MPa and Young’s modulus of 1498 MPa. Grey Relational Analysis (GRA) confirmed this parameter set as optimal, yielding the highest Grey Relational Grade (0.8230). SEM analysis revealed uniform filler dispersion and reduced porosity, while surface roughness decreased by ~65% (Ra reduced to 25.04–28.92 μm). Thermogravimetric analysis demonstrated enhanced thermal stability, with residual mass increasing from 2.89% (pure PLA) to 8.18% for the composite. The results confirm the synergistic reinforcement effect of SiC (ceramic stiffening phase) and MoS 2 (interfacial stress redistribution phase), establishing the developed hybrid filament as a promising candidate for rigid, thermally stable 3D-printed components.