Characterization of 3D printed polylactic acid composites with varying carbon black concentrations manufactured by material extrusion process

Abstract The advances in 3D printing technology has opened new opportunities in diverse functional areas. This has also impact on the global quest for sustainable polymer processing of biodegradable materials with additives to enhance their functional properties. This study investigates the impact of acetylene-grade 50% compressed carbon black (CB) additive on selected properties of biodegradable polymer PLA for potential use in textile printing. The CB reinforced composite samples were fabricated using MEX based 3D printing and tests were conducted. Filaments reinforced with 1.5, 2.5, and 3.5 wt% CB loading were fabricated using particles averaging 75 ± 2 nm. Then, tensile, hardness and microstructural properties were investigated. The Young’s modulus of PLA/CB composites are observed to be lower than or equal to that of pure PLA (2.9 GPa) except 2.5 wt% CB (3.9 GPA), which also demonstrated the highest average tensile strength (39.46 MPa) comparable with pure PLA (40.85 MPa). On the other hand, the strain at failure for all CB reinforced samples is lower than that of PLA (0.84%). The lowest strain at failure (0.52%) is registered for 2.5 wt% CB. The microscopic analysis also revealed increased voids and defects due to CB particle agglomeration, though no major microstructural changes were observed. Additionally, the 3.5 wt% CB sample exhibited the highest average hardness (81.40 N). In summary, the 2.5 wt% CB is observed to have equivalent mechanical properties with pure PLA and the reinforced CB will add other functional values such as electrical conductivity, which is a continuing study.