The potential for release of engineered nanoparticles from polymer nanocomposites used in consumer applications is a topic of interest to environmental scientists, toxicologists, and consumer product stakeholders. The benefits of using nanocomposites over traditional plastics have been well established since these materials were first reported in the early 1990’s, and include: higher strength, attenuated gas diffusion barriers, biocidal properties, and engineered activity, such as the ability to actively respond to changes in environmental conditions. In the specific case of polymer nanocomposites intended for food packaging applications, there is a need to address whether, and under what conditions, nanoparticles can be released from polymer nanocomposites into food matrices or into the environment during the post-consumer stage. To address these questions, we devised a model system wherein fluorescent quantum dot (QD) nanoparticles were effectively dispersed in a low density polyethylene (LDPE) matrix by melt-mixing. QD/LDPE films were extruded and fully characterized by a suite of microscopy and thermal analysis techniques; notably, these materials were seen to retain the fluorescence of QDs after thermal processing. The QD/LDPE films were then tested for nanoparticle release into neutral and acidic aqueous media for varying lengths of time at 75 °C, conditions chosen to represent a “worst case scenario” for a food packaging application. These experiments, analyzed by a combination ICP-MS, TEM, and confocal scanning laser microscopy, showed evidence of nanoparticle release into the external medium, primarily in the form of dissolved ions, both from the surface and interior volume of the test material. These results yield new insight into engineered nanoparticle release mechanisms and constitute an important contribution to the engineered nanomaterial health and environmental safety knowledge base.

Evaluation of nanoparticle release from polymer nanocomposites loaded with fluorescent quantum dots

249th National Meeting (2015)

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