Polymer based nanocomposites – enabling innovation, resource efficiency and helping to fight climate change
A «Nanopinion» by Dr. Sabine Lindner from PlasticsEurope Germany, published on the EUON website sheds an interesting light on the role of nanoparticles in food packaging plastics, how possible risks are managed and what gaps are still open to drive and support innovation in nanotech industries.
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 speci¬fied 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.
Building alliances for pushing boundaries
In addition to supporting research activities, PlasticsEurope is active in cooperating with different stakeholders.
One example is the International Nano Authorities Dialogue.
The government dialogues revolve around the adequacy of regulation of nanomaterials in the field of health and environmental protection. For a few years, representatives of European authorities have participated in the discussions , e.g. the European Nano-Observatory (EUON) and the Joint Research Center of the European Commission (JRC) have presented their work. Internationally, the activities of the OECD with regard to test protocols for nanomaterials were discussed.
This government dialogue began already in 2006 and takes place once a year. It is an element of close cooperation between Germany, Liechtenstein, Luxembourg, Austria and Switzerland. The aim of the cooperation is to observe, reflect on and, where appropriate, support sustainable development in the field of nanotechnologies through stakeholder activities.
Another example of successful cooperation is the participation in the advisory board of the RiskGone project, started in February 2019.
RiskGONE is an EU H2020 project, aiming at providing solid procedures for science-based risk governance of nanomaterials, based on a clear understanding of risks and risk management practices. It will allow the European Union to fully exploit the economic and social potential of engineered nanomaterials and nanotechnologies broadly. A first critical step is the provision of an integrated science and societal decision framework for engineered nanomaterials risk governance.
Despite significant progress achieved in research regarding the safety of engineered nanomaterials and the transfer of this knowledge into standardisation and regulation, there is still an urgent need to establish the scientific basis for assessing the risks of engineered nanomaterials to support nanotechnology industries, regulatory bodies and risk assessors with clear and user-friendly processes for risk evaluation, management and transfer; in other words, for risk governance and acceptance based on standardised methods.
This knowledge transfer is crucial in order to implement a robust and reliable methodology for the risk assessment of engineered nanomaterials via decision-making tools that are applicable across different industrial sectors and facilitate risk communication to relevant stakeholders, including industry, regulators, insurance companies, civil society organisations and the general public.