Abstract

In this study, antimicrobial nanocomposites based on low-density polyethylene (LDPE) and calcium oxide nanoparticles (CaO) were developed for potential use in food packaging. CaO nanoparticles, averaging 5.6 ± 1.8 nm in diameter, were synthesized from eggshells and surface-modified with oleic acid (O-CaO). Nanocomposites were prepared via melt-blending, incorporating nanoparticles into neat LDPE at 5 and 10 wt% concentrations. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed improved distribution and dispersion of O-CaO nanoparticles within the polymer matrix compared to unmodified CaO. This enhanced dispersion increased the crystallinity percentage (%Xc) of LDPE/O-CaO from 14 % to 18 %. Mechanical testing showed a 22 % increase in Young's modulus for nanocomposites with 5 wt% O-CaO, with dynamic mechanical thermal analysis (DMTA) confirming increased stiffness at low temperatures. The nanocomposite films exhibited high antimicrobial efficacy, reducing Escherichia coli populations by over 74 %, dependent on nanoparticle surface modification. These findings suggest that LDPE/O-CaO films are a promising alternative for antimicrobial food packaging applications. © 2024 Institution of Chemical Engineers (IChemE)