Z-axis 3D-printing performance improvement by modifying polylactic acid composites using microcrystalline cellulose...

Polylactic acid (PLA) is a polymer exhibiting good biocompatibility and biodegradability; however, because of its high brittleness, its application to three-dimensional (3D) printing is limited. In addition, the z-axis printing performance of PLA materials is poor, resulting in weak interlayer forces; as a result, balancing printing accuracy and performance is difficult. Herein, to overcome this problem, polybutylene adipate-co-terephthalate (PBAT) and microcrystalline cellulose (MCC) were used to modify PLA composites; additionally, ionic surfactants, the green plasticizer tributyl citrate (TBC), and the epoxy chain extender ADR4468 were used to improve compatibility among PLA, MCC, and PBAT. The objective was to improve the toughness and z-axis PLA 3D-printing performance. After modification, the fracture elongation of the PLA 3D-printing spline substantially increased from 61.8 % to 434.2 %. By incorporating 1.5 % ADR4468, the tensile strength of the spline increased to 36.9 MPa (a 33.2 % increase). Regarding the z-axis printing performance, the tensile strength of the spline increased to 15.9 MPa, enabling the fabrication of dumbbell-shaped samples along the z-direction. In contrast, neither commercial PLA 3D-printing filaments nor those modified using PBAT could be fully used for printing along the z-axis. In this study, a feasible approach for producing PLA-based 3D-printing products with excellent z-axis printability is presented, broadening the application of PLA composites in the field of 3D printing.