ASA / spherical Cu nanocomposites in MEX additive manufacturing: a comprehensive interpretation of the engineering and biocidal multi-functionality

• The aim herein was the development of multifunctional nanocomposites suitable for material extrusion additive manufacturing. • Acrylonitrile styrene acrylate was the matrix and copper nanopowder (spherical particles) was filler, with nanocomposites prepared and studied at various concentrations. • The mechanical properties were improved (14.5% in the tensile test at the 8 wt.% content). • Sufficient antibacterial performance was found for the S. aureus and the E. Coli bacteria. Multifunctional polymeric nanocomposite filaments encounter excessive demand from the material extrusion (MEX) additive manufacturing (AM) industry and rigorous end users. Herein, the fabrication, characterization, and optimization of nanocomposites based on a recent Acrylonitrile Styrene Acrylate (ASA) copolymer filled with copper (Cu) spherical nanoparticles is accomplished. The objective of this investigation was to develop efficient nanocomposites for the MEX AM method with combined features, i.e., enhanced printability and thermomechanical and biocidal properties. The effects of Cu nanoparticle loading on the mechanical, rheological, thermophysical, and biocidal properties of 3D printed parts are reported herein. The ASA/Cu nanocomposite filaments were prepared by dispersing spherical Cu nanoparticles into the ASA matrix through melt-filament extrusion. The composite filaments were then used to fabricate standard 3D-printed specimens. A significant improvement in mechanical strength was observed at certain Cu loadings (more than 14.0% in tensile and flexural strength and more than 10% in the respective stiffness properties at 8 wt. % Cu). Biocidal metrics were documented against two pathogens, Staphylococcus aureus and Escherichia coli. The agar-well diffusion method was employed, and strong biocidal metrics were reported compared with the reference antibiotics. The multi-functionality of the nanocomposites developed is discussed in depth herein and is associated with the strong polymer bonding with the Cu filler, considering the nano-roughness observed on the spherical nanoparticles.