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 (%X c ) 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.

P. Zapata and F. Melo thanks the Universidad de Santiago de Chile, Usach. Proyecto Dicyt 052241ZR_DAS, Vicerrectoría de Investigacion, Desarrollo e Innovación. V. Moreno-Serna acknowledges the financial support of ANID FONDECYT Iniciación 11240437. J.A. Ortiz thanks for the financial support of ANID FONDECYT Iniciación 11230657. T. Corrales thanks the funding to MICINN (Project Ref. PID2021- 124926NB-I00)

Peer reviewed