Preparation of polycarbonate/poly(lactic acid) with improved printability and processability for fused deposition modeling

Fused deposition modeling (FDM) is the most widely used 3D-printing technology due to its simplicity to operate and low cost. However, many engineering plastics such as polycarbonate (PC) with better properties cannot be applied in common FDM printer because of their poor processability and printability. Poly(lactic acid) (PLA) as the most common printing material has the disadvantages of insufficient heat resistance and poor toughness, which limits the application of PLA-based FDM product in more potential fields. To develop new material available for FDM, PC/PLA blend was prepared by polymer blending and achieved essential printability for FDM. Ethylene-butyl acrylate-glycidyl methacrylate terpolymer (PTW) was introduced to PC/PLA blend as warpage modifier and also had a good toughening effect. Thus, PC/PLA/PTW blend had been prepared as FDM filament with excellent comprehensive properties. The phase morphology of PLA changed from independent dispersed phase to semi-continuous phase with increasing PLA content. Different from the injection molding samples, the morphology of FDM-printed samples indicated that the PLA phase oriented in the same direction due to the tensile orientation of the filaments caused by nozzle scanning. Five printing modes were designed to study the effect of printing direction on mechanical properties and failure modes. It was proved that the adhesion between the filaments was weaker than the strength of filament itself and easily caused adjacent filament exfoliation, ultimately resulting in the failure. The work provided some referential conclusions contributing to optimization of printing strategy.