3D Printed BioPE Textile for Low Temperature Applications

The developments in polymer material synthesis and manufacturing processes are re-shaping the textile industry, ushering in a new textile manufacturing paradigm, namely implementation of digital and sustainable manufacturing approaches, such as fused deposition modelling (FDM) 3D printing. In recent years, 3D printing of polymers on textiles has shown a lot of potential to optimize complex designs, automate manufacturing as well as to develop new textile functionalities and aesthetic elements. Most popular polymers printed on textiles include polylactic acid, acrylonitrile butadiene styrene, nylon, polycarbonate, glycol modified poly-ethylene terephthalate, and thermoplastic polyurethane. They are usually printed on a dissimilar textile material, which leads to poor adhesion between the printed parts and the fabric. In addition, poly-material nature of the state-of-the-art 3D printed textiles often makes it impossible to separate and reclaim their ingredients at the end of the product lifecycle. Furthermore, conventional 3D printable polymers are typically stiff and have poor thermal management properties, which may cause thermo-physiological wear discomfort of 3D printed textiles. Overcoming these challenges will significantly improve wear comfort, sustainability of 3D printed textile and drastically expand their functionality.<br/><br/>This work aims to develop bioderived, low-carbon-footprint monomaterial 3D printed textile platform for low temperature applications in defense and aerospace industries. We explore the role of the nanostructure of bioderived polyethylene (bioPE) 3D printed structures in engineering their tensile and elastic performance at extremely low temperatures (down to -70 °C). A range of bioPE yarns and textile with various 3D printed patterns and different nano-scale structure has been fabricated via a combination of a scalable fiber melt-extrusion method and fused deposition modelling. These yarns and textiles have been characterized by their tensile and viscoelastic performance, as well as classified according to their meso- and nanoscale structure. Wide angle (WAXS) and small angle (SAXS) X-ray scattering techniques confirmed that by precise engineering of bioPE material nanostructure, we can tune the material crystallinity degree from ~60% to ~80% and to achieve high degree of crystalline domain orientation along the fiber axis. This tunability of the fiber nanostructure translates into tunable elongation at break (up to ~100%) and tensile strength (up to ~180 MPa) values of the bioPE yarns at -70 °C. We further show that mono-material bioPE 3D printed textiles exhibit great adhesion between the printed parts and the fabric, together with high flexibility and durability. In addition, bioPE 3D printed textiles are fully recyclable into a high-value and utility material stock. Overall, our work provides novel route towards development of lightweight, multifunctional bioPE 3D printed textiles with potential applications from uniforms and wearables to aerospace suits, while offering lower environmental footprint in production and full mechanical recyclability.<br/><br/>This work was supported by the Advanced Functional Fabrics of America (AFFOA) and the US Army Research Office. We thank Brandon Henry, Michael Lampkin, Tony DeLaHoz and Jeff Haggard from Hills Inc. for help with the PE yarns fabrication and Braskem for providing bio-derived PE resins. A.H. was supported by NSF GRFP. Useful discussions with Leslie Yan, Michael Rein, and Michelle Farrington are gratefully acknowledged. We also thank Steven Kooi for his help with equipment installation.