Electrical conductivity and microstructural features of 3D-printed PLA-CB composites fabricated at different temperatures

The growing interest in sustainable and functional materials for additive manufacturing has stimulated the development of electrically conductive polymer composites. In this context, polylactic acid (PLA) reinforced with carbon black (CB) emerges as a promising and environmentally friendly candidate for lightweight electronic applications. Despite advances in conductive composite formulations, the influence of key printing parameters, particularly printing temperature, on the electrical and structural behavior of PLA-CB systems remains underexplored. This study examines the impact of printing temperature on the electrical conductivity, structure, and heat resistance of PLA-CB composites containing 40 wt% carbon black. We conducted electrical characterization by measuring resistivity and conductivity under different extrusion temperatures and applied voltages. Structural modifications were evaluated using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR), while scanning electron microscopy (SEM) was used to examine filler dispersion and interfacial adhesion. Neat PLA served as a control. Our findings reveal a strong correlation between printing temperature and both electrical performance and microstructural organization. We also identified a critical voltage threshold at which the composite undergoes thermal degradation. These results highlight the pivotal role of thermal processing parameters in optimizing the functional properties of PLA-CB composites and provide insights for the design of cost-effective, sustainable materials for 3D-printed electronic applications.