A comprehensive feasibility study on the properties of LDPE-Ag nanocomposites for food packaging applications

The intense recent interest in active food packaging with silver nanoparticles (AgNPs) is attributed to the extraordinary efficacies of the AgNPs against a broad-spectrum of food-borne pathogens. A comprehensive study of silver nanocomposites was conducted to identify the effect of the AgNPs on the properties of low-density polyethylene (LDPE) for food packaging applications. The investigation included the study of the optical, thermal, mechanical, and barrier properties, as well as antimicrobial activity against Gram-positive and Gram-negative bacteria. Upon addition of AgNPs in LDPE, LDPE-AgNP composite films became less transparent and more yellowish because of surface plasmon resonance vibrations of the AgNPs. The SEM, EDS, and TEM results revealed that spherical AgNPs were distributed on both surface and interior of the LDPE film. While these well-dispersed AgNPs enhanced the barrier properties of LDPE for both oxygen and water vapor, the incorporation of AgNPs impinged onto the thermal properties by reducing the thermal stability and the melting enthalpy of the LDPE film. In addition, LDPE-AgNP composite film showed effective antibacterial activity against Staphylococcus aureus and Escherichia coli. These findings suggest that the LDPE-AgNP composite film can be feasibly used in food packaging to preserve the food quality and extend the shelf-life of the product. POLYM. COMPOS., 39:3178-3186, 2018. (c) 2017 Society of Plastics Engineers