(404h) Evaluation of UV-Curable Polymeric Binders for Additive Manufacturing Construction in Space Environments

Building infrastructure on other planetary bodies requires the use of locally derived resources to be economically feasible. Regolith present on the Moon and on Mars have been evaluated as potential substitutes for the coarse and fine aggregates of terrestrial concrete. However, due to the extreme environments of the Moon or Mars, including sub-zero temperatures and low atmospheres, as well as the limited resource production and prioritization of life-support equipment, mimicking the binder solidification of concrete through hydration and solvent evaporation is not practical. Here, we propose an alternative binder solidification mechanism by exploring the use of an additive manufacturing method, direct-ink-write (DIW), combined with UV-curing of the binder and a comparison of the processability of the binder-particle system at room temperature and in sub-zero environments. We assess different formulations of photocurable polymers, in which we suspend model regolith particles, through rheological characterization to determine formulation parameters resulting in continuous extrusion for DIW. Through yield stress and thixotropy testing, as well as through visual comparison using SEM, we evaluate ratios of pre-polymer to monomer within the scope of required extrusion force and post-extrusion microstructural recovery. We use TGA to assess shear-induced phase separation in the nozzle as a result of varying the binder formulation and the particle modality. By fundamentally understanding the interplay between the binder and the particles during DIW printing, both in ambient terrestrial conditions and in simulated Martian climates, we demonstrate the potential of polymeric UV-curable binders and AM as a cost-effective solution to off-Earth construction.