Industrially scalable reactive melt mixing of polypropylene/silver nitrate/polyethylene glycol nanocomposite filaments: Antibacterial, thermal, rheological, and engineering response in MEX 3D-printing

Abstract

This research focused on developing medical-grade polypropylene (PP)/silver (Ag) nanocomposites for the production of components through material extrusion (MEX) three-dimensional printing (3DP). The objective was to improve the performance of PP by enhancing its mechanical properties and imparting antibacterial characteristics. An industrially scalable process was utilized to fabricate PP/Ag nanocomposites through the reactive melt mixing technique. Polyethylene glycol (PEG) served as the reduction agent, and silver nitrate (AgNO3) was incorporated as the additive. During the extrusion of the three-dimensional printing (3DP) filaments, reactive melt mixing occurred, resulting in the production of specimens for various standard tests. The addition of 5.0 wt% AgNO3 and 2.5 wt% PEG in the PP thermoplastic led to a slight improvement in mechanical performance, with a 9.9 % increase in tensile strength observed. The antibacterial properties of the composites were assessed through agar well diffusion tests against Escherichia coli (E-coli) and Staphylococcus aureus (S. aureus). A more significant biocidal effect was observed for S. aureus compared to E-coli. These composites have the potential to be utilized in industrial applications that require enhanced mechanical properties and durability, as well as important biocidal properties, such as in the medical equipment industry or the defense sector.

Keywords

• Polypropylene (PP)
• Polyethylene glycol (PEG)
• Silver nitride (AgNO3)
• Reduction agent
• Material extrusion (MEX)
• In-situ reactive melt mixing process