Flexible Thermoplastic Polyurethane Composites with Ultraviolet Resistance for Fused Deposition Modeling 3D Printing

Currently, there is great demand for flexible three-dimensional (3D) printable thermoplastic polyurethane (TPU) wires with excellent ultraviolet (UV) resistance, which have broad application prospects in wearable products. In this study, UV-resistant TPU composites were obtained using a blending modification method. The relationship between the optimized parameters of fused deposition modeling 3D printing and mechanical properties of the TPU composite is discussed using an orthogonal test. This study observed that the UV absorption properties of TPU composites were enhanced, and the TiO₂ and TiO₂/ZnO fillers improved the tensile strength of TPU composites. After UV aging, the tensile strength and elongation of the TPU composite slightly decreased, but were still much higher than those of pure TPU. Among the printing parameters, printing speed had the greatest influence on the mechanical properties of TPU composites. When the printing speed was 80 mm/s, printing layer thickness was 0.25 mm, nozzle temperature was 220°C, and hot bed temperature was 50°C, the TPU composites exhibited the best elongation at break and tensile strength. After regression analysis, two regression models for the elongation at break and tensile strength of TPU composites were obtained and verified, which provide a reference for predicting the relationship between the printing parameters and mechanical properties of flexible TPU composites.