Surface Heterogeneity at the Polymer-Food Interface Influences Ag Migration from Plastic Packaging Incorporating...

Area of Science:

• Materials Science
• Food Science
• Polymer Chemistry

Background:

• Silver-enabled polymers offer antimicrobial properties for food packaging.
• Understanding silver (Ag) migration from polymers to food is crucial for quality and safety.
• Ag-exchanged zeolites (Ag-Y) are explored as scaffolds for high Ag loading in polymers.

Purpose of the Study:

• To investigate Ag migration from two types of Ag-Y/LDPE polymer composites into food simulants.
• To compare Ag release from ionic Ag⁺ and nanoparticulate Ag (AgNPs) incorporated into LDPE.
• To understand the influence of Ag form and food simulant composition on Ag migration.

Main Methods:

• Manufactured two Ag-Y/LDPE films: one with Ag⁺ and one with AgNPs, with similar initial Ag concentrations.
• Assessed Ag migration into water, sucrose solution, and a carbonated beverage under accelerated storage conditions (40 °C).
• Utilized surface characterization techniques (AFM, SEM, conductivity) to analyze film surfaces and zeolite particle exposure.

Main Results:

• Ag⁺-Y/LDPE films exhibited significantly higher Ag migration than AgNP-Y/LDPE films across all food simulants.
• Ag migration from AgNP-Y/LDPE ranged from 7.63 to 21.29 ng cm^-2, while Ag⁺-Y/LDPE showed migration from 49.61 to 91.54 ng cm^-2.
• Surface analysis indicated exposed zeolite particles, suggesting direct interactions at the simulant-polymer interface influence Ag migration.

Conclusions:

• The form of silver (ionic vs. nanoparticulate) in Ag-Y/LDPE significantly impacts Ag migration into food simulants.
• AgNP-Y/LDPE demonstrates lower, potentially more controlled, silver release compared to Ag⁺-Y/LDPE.
• Surface interactions between the polymer composite and food components are key factors governing silver migration in food packaging applications.