Mechanical, thermal, and antimicrobial behavior of copper-enhanced polypropylene composites with improved UV stability

This study investigates the incorporation of copper nanoparticles (Cu NPs) into polypropylene (PP) matrices to enhance mechanical, thermal, and antimicrobial properties, addressing the growing challenge of antimicrobial resistance (AMR). Cu NP–PP composites were fabricated using twin-screw extrusion and injection molding, with nanoparticle concentrations of 0%, 1%, 2%, 5%, and 10%. Mechanical testing revealed that lower Cu NP loadings (1%–5%) improved yield strength (by 2%–5%) and elastic modulus (by 1.2%–1.9%), while higher concentrations (≥5%) led to performance reductions due to stress concentration effects. Thermal analysis demonstrated increased stability, with TGA onset and peak degradation temperatures rising from 445 °C and 469 °C (pure PP) to 455 °C–462 °C and 475 °C–481 °C, respectively, in Cu NP–reinforced composites. DSC results showed higher crystallinity retention in Cu NP–PP composites (40.8%–50.2%) compared to pure PP (41.7%). Furthermore, Cu NPs imparted significant antimicrobial efficacy, particularly against Gram-negative bacteria such as Pseudomonas aeruginosa. In addition, a minor improvement in UV stability was observed, suggesting secondary protection of the polymer matrix against photodegradation. These findings highlight the multifunctional potential of Cu NP–PP composites for healthcare and outdoor applications, offering a promising approach to mitigating AMR-related risks while enhancing durability. • Copper nanoparticle-polypropylene composites were fabricated via twin-screw extrusion and injection molding across 0-10 wt% concentrations. • Systematic evaluation revealed 1-2 wt% as optimal for enhancing mechanical properties, increasing yield strength by 5% and resilience by 6.8%. • Comprehensive aging studies (1000 hours) demonstrated exceptional property retention, with Cu-PP maintaining over 90% of tensile strength versus 58% for pure PP. • Multi-technique characterization (TGA/DSC) confirmed enhanced thermal stability and crystallinity, with degradation temperatures increasing by up to 13°C. • The composites exhibited multifunctional performance, combining antimicrobial efficacy against P. aeruginosa with improved UV durability for outdoor applications.