3D Printing of Liquid Crystal Polymers for Space Applications

Fused Filament Fabrication is a promising manufacturing technology for the circularity of space missions. Potential scenarios include in-orbit applications to maximize mission life and to support long-term exploration missions with in situ manufacturing and recycling. However, its adoption is restricted by the availability of engineering polymers displaying mechanical performance combined with resistance to space conditions. Here, a thermotropic Liquid Crystal Polymer (LCP) is reported as a candidate material with extrusion 3D printing. To expand its scope of applicability to structural parts for space applications, four different exposure conditions are studied: thermal cycling under vacuum, atomic oxygen, UV, and electron irradiations. While 1 MeV-electron irradiation leads to a green coloration due to annealable color centers, the mechanical performance is only slightly decreased in dynamic mode. It is also found that increased printing temperature improves transverse strength and resistance to thermal cycling with the trade-off of tensile stiffness and strength. Samples exposed to thermal cycling and the highest irradiation dose at lower printing temperatures still display a Young's modulus of 30 GPa and 503 MPa of tensile strength which is exceptionally high for a 3D-printed polymer. For the types of exposure studied, overall, the results indicate that LCP 3D-printed parts are well suited for space applications. Three-dimensional printed thermotropic liquid crystal polymers (LCP) exhibiting high tensile strength and stiffness, are found to withstand thermal cycling, atomic oxygen, UV, and electron irradiation. Notably, 1 MeV-electron irradiation induces green coloration from annealable color centers, without significantly compromising mechanical performance, affirming LCP's suitability for space applications. image