Tensile properties of 3D printed structures of polylactide with thermoplastic polyurethane

Multi-material forming in three dimensional (3D) printing is drawing attention because of its larger functionality. In this paper, dissimilar materials sample involving polylactic acid (PLA) and thermoplastic polyurethane (TPU) were prepared in laminating via fusion deposition modeling (FDM) 3D printing technology, and they varied volume fraction of TPU and material layouts. Compared with the 3D printed samples of single PLA and single TPU, the tensile behaviors of the PLA/TPU sample with dissimilar materials were examined. The results found that the tensile strength and elastic modulus of 3D printed PLA/TPU were sensitive to TPU volume. A model for predicting and evaluating the tensile strength of 3D printed PLA/TPU was proposed, which was verified by the experimental data. Furthermore, at a given volume ratio of TPU, PLA/TPU samples with different material layouts showed distinct tensile performances. Besides, the specimen surface morphology and the fracture topography of PLA/TPU samples were observed by scanning electron microscopy. The underlying failure mechanisms of these dissimilar material printed specimens were investigated. The findings enable designers to design more reliable multi-material structures for 3D printed parts.