Multifunctional Acrylonitrile Styrene Acrylate/Cuprous Oxide Nanocomposites in MEX 3D Printing: Rheological, Thermomechanical and Antibacterial Metrics

To address the critical need for robust and self‐sterilizing materials for challenging environments, this research introduces the use of cuprous oxide (Cu 2 O) nanoparticles in weatherproof acrylonitrile styrene acrylate (ASA) through material extrusion (MEX) 3D printing to produce multifunctional nanocomposites with improved mechanical, rheological, and antibacterial properties. A range of ASA/Cu 2 O compositions (0.5–3.0 wt.% filler loading) was compounded and extruded into filament, and then specimens were fabricated using MEX 3D printing. Thermal properties of the nanocomposites were evaluated by thermogravimetric analysis and differential scanning calorimetry; the rheological behavior and printability were determined by melt viscosity and melt flow rate measurements. The influence of Cu 2 O content on printed part quality was evaluated by using micro‐computed tomography (dimensional accuracy and porosity were quantified). Incorporation of Cu 2 O improved the mechanical properties by 13%–30% (tensile strength 16.6%–46.4 MPa, flexural strength 23.2%–67.5 MPa, toughness about 30%) compared to the neat matrix. The 1.5 wt.% composition showed the best overall mechanical performance. The antibacterial properties were confirmed by the agar well diffusion method against Gram‐negative bacteria ( E. coli ) and Gram‐positive bacteria ( S. aureus ). The simultaneous structural reinforcement and biocidal properties in a single material without sacrificing processability or geometrical accuracy render ASA/Cu 2 O a promising nanocomposite for components in the MEX 3D printing process in outdoor and public‐hygiene applications.