Additive manufacturing of PEKK composites with selected Martian regolith particles for in-situ resource utilization

Sustainable in-situ resource utilization (ISRU) requires materials and processes that minimize Earth dependency while enabling autonomous construction on Mars. This study investigates the fabrication and characterization of polyetherketoneketone (PEKK)/Martian Regolith Simulant (MRS) composite filaments optimized for additive manufacturing. By systematically reducing MRS particle size (<100 μm, <50 μm, and < 20 μm), the achievable filler loading in pulverized PEKK was progressively increased to 30 wt% without phase segregation. Filaments were produced using twin-screw extrusion and comprehensively characterized through rheological, thermal, and microstructural analyses prior to material extrusion (MEX) printing. Mechanical and thermomechanical testing of 3D-printed parts revealed that particle morphology and size distribution significantly influence porosity, interlayer adhesion, and anisotropy. SEM and EDX analyses confirmed uniform MRS dispersion and matrix infiltration into perforated silicate particles, facilitating enhanced strand fusion. At high filler contents, mechanical strength plateaued, indicating a transition in fracture mechanisms rather than continued degradation. Dynamic Mechanical Analysis (DMA) demonstrated consistent elastic behavior between 0° and 90° orientations, while thermal post-processing enhanced thermal stability but introduced porosity, particularly at intermediate filler levels. A tensile strength model incorporating filler volume fraction, porosity, and fracture mode accurately predicted experimental results across compositions. These findings establish high-loading PEKK/MRS composites as a viable material system for sustainable, recyclable ISRU-based additive manufacturing on Mars. • Developed PEKK/MRS composite filaments with up to 30 wt% regolith for AM-ISRU. • Optimized MRS particle size to achieve uniform dispersion without solid-phase segregation. • Demonstrated anisotropic mechanical behavior with inter-strand reinforcement by MRS. • Thermal post-processing improved thermal stability but affected porosity evolution. • Proposed predictive tensile strength model integrating filler fraction and porosity effects.