Polymer/Noble Metal Nanocomposites: A Model System to Assess Exposure to Nanotechnology-Enabled Food Packaging Materials

Polymer nanocomposites (PNCs), in which nanofillers are added into a polymer matrix, can be engineered to show improved barrier properties and increased mechanical strength. PNCs also have potential use as intelligent chemical or biological sensors. With respect to the use of PNCs as food packaging materials, there is a need for additional information about the possibility of release of nanofillers into food or the environment. Many previous studies on nanofiller exposure have used PNCs incorporating polydisperse samples of nanoparticles (NPs), and thus yielded results that can be difficult to interpret. Therefore, more systematic studies of NP release into the environment would be useful. Here, several sizes of Ag NPs were synthesized and mixed into low density polyethylene (LDPE) to create PNC films with well-controlled nanofiller characteristics. The release of Ag NPs or their components into model food contact substances, such as water and dilute acetic acid was tested and quantified by ICP-MS, STEM, and optical measurements. To determine the role of NP stability and composition, Ag ₂ S and Au NP/LDPE PNCs were tested as well. This work is an example of an experimentally controlled lifecycle analysis when it comes to PNCs in the environment.