Characterization of polylactic acid/thermoplastic polyurethane composite filaments manufactured for additive manufacturing with fused deposition modeling

Polylactic acid and thermoplastic polyurethane (TPU) were mixed in different proportions and extruded through twin-screw and single screw extruders to obtain composite filaments to be used for additive manufacturing (3D printing) with fused deposition modeling method. The properties of the filaments were characterized using uniaxial tensile tests, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, rheology, polarized optical microscope, and scanning electron microscope. 3D printed samples from composite filaments were tested using dynamic mechanical analysis. It was found that the tensile strength and modulus of the filaments decrease while elongation at break increases with the increasing TPU content in the composite. The analysis also showed a partial miscibility of the polymer constituents in the solution of composite filaments. Finally, a flexible structure, plain weave fabric, was designed and 3D printed using the composite filaments developed which proved that the filaments are well suited for 3D printing.