Polymer based nanocomposites—enabling innovation, resource efficiency and helping to fight climate change

2020-07-01

The plastics industry in Europe is a vibrant sector that helps improve our quality of life by enabling innovation, facilitating resource efficiency and enhancing climate protection.

When thinking of how nanoscale particles that are added to plastic matrices can improve the properties of products, a lot of examples come to mind – for instance, the electrical or thermal properties of electrostatic packaging for microchips, electrostatic coatings, solar cells, batteries, modified lithium-ion batteries or printed electronics.

Nanoscale particles can also increase mechanical resilience of reinforced plastics used for the construction of lighter cars and planes or for the blades and wind turbines.

Moreover, they are added to modern plastic packaging for improving its material properties – e.g. thermal stability, barrier properties, UV protection.

Plastic packaging plays an important role in ensuring the freshness of food, extending its shelf life and helping to improve the quality of products for consumers. According to recent data, around 20% of food produced in the EU is lost or wasted. Plastic packaging can help make food increasingly accessible, safe and affordable.

Migration of substances into food occurs with all packaging

Migration happens whenever packaging — of any type — comes into contact with food. It is a natural physical process. The key point is that the level of migration is safe.

EU Regulation 10/2011 on plastic materials and articles intended to come into contact with food, authorises some of them as additives for plastics in food contact with certain requirements. Additives are like spices in a cooking recipe.

Nanoparticles are deliberately incorporated in the plastic matrix. But do they remain firmly bound in the plastic packaging materials also in real use conditions?

Before answering this question and to better understand what real use conditions mean, let’s think of our daily life. Real use conditions mean that you do not put a reusable plastic bowl in the oven to warm your food, as it is not intended to be used at a high temperature, unless specifically indicated on the product.

Plastics are rigorously tested to make sure that migration – if any – is safe

Testing conditions are specified legally and need to be used by all actors performing tests in the value chain (from raw materials and packaging producers to food packers). Tests are done at several stages in the value chain to ensure that the plastic sample is suitable for its end-use.

PlasticsEurope together with Cefic-FCA – the food additive sector group of the Chemical association CEFIC – collaborated with the Fraunhofer Institute for Process Engineering and Packaging (IVV) to examine whether nanoparticles can migrate from plastic packaging into the packaged foodstuff.

In migration testing it is useful to differentiate between two types of nanoparticles, based on their morphological structures: lamellar (flat) nano-clays and (quasi-) spherical particles (e.g. silver or titanium nitride). Temperature and time-dependent experiments were performed in the polymer (LDPE).

Three plastic nanocomposites containing the nanomaterial silver, titanium nitride and laponite were investigated on the potential to release nanoparticulates under stress conditions into food simulants.

What are food simulants, you might ask? Food simulants – as prescribed by law (e.g. olive oil) – mimic the properties of different food types under typical/worst case conditions.

The results of the study conclude that laponite does not migrate into food once it is incorporated into a polymer matrix.

While laponite represents lamellar types of nanoparticles, another experimental set up could show that also spherical types of nanoparticles, like silver nanoparticles in an LDPE (Low-density polyethylene) plastic matrix cannot migrate.

In a nutshell, the studies demonstrated, that nanoparticles which are completely encapsulated in the host polymer matrix do not have a potential to migrate into food and therefore consumers will not be exposed to nanoparticles from food contact polymers when those are completely embedded in polymer and the contact surface is not altered by mechanical surface stress during application.

Full Article

EUON, 1 July 2020
; https://euon.echa.europa.eu/de/nanopinion/-/blogs/polymer-based-nanocomposites-enabling-innovation-resource-efficiency-and-helping-to-fight-climate-change