Finding ways to reduce the amount of plastic used in food packaging, while still ensuring products are protected and kept fresh, is an increasingly important challenge. James Baker, Chief Executive Officer of Graphene@Manchester, explains how the answer could lie in the use of novel 2D materials.

• Changes in consumer perception and behaviour relating to plastic packaging are underway, with many shoppers trying to reduce consumption; and shops and manufacturers are responding.
• There are genuine benefits for companies which can motivate them to reduce plastic use in food packaging in particular, where wasted food is an increasingly important issue both socially and commercially.
• Graphene has many potential applications in food packaging, primarily in making thinner and stronger materials, creating better selective barriers, and improving the barrier performance of biodegradables.
• The National Graphene Institute (NGI) is looking at several possible new ways to use graphene and other 2D materials in an array of application areas including food packaging.
• The NGI is also working with industrial partners on solutions for speeding up R&D which has the potential to both improve the UK’s productivity and reduce global plastic use.

Over recent months there has been a huge increase in public awareness of the environmental impact that plastics in food packaging are having. This was highlighted in the 2018 BBC series “Blue Planet II” and I have started to see some very interesting changes in the public’s approach to buying products with reduced plastic packaging to minimise the potential damage to the environment.

An example of this is an increase in the number of consumers returning to the traditional form of milk purchasing with returnable glass bottles delivered by the milkman direct to buyers’ homes. However, consumers need to be aware of the environmental impacts of any change to their behaviour – glass bottle production, washing and transport also have an effect on the environment.

Plastic is a cheap and versatile material, but the increasing demand by the public for large supermarkets and retailers to reduce its use is leading many to take notice. Several of the biggest supermarkets in the UK have recently ended the sales of temporary 5p plastic bags in exchange for longer-lasting options and in the Netherlands a supermarket recently opened a plastic-free aisle.

But while many existing plastic reduction activities are based around recycling, the main driver in the food packaging industry is usually reducing food waste by improving food protection during transit and extending shelf lives. The Food and Agriculture Organization (FAO) of the United Nations states that around a third of all the food produced in the world is lost or wasted, and the Waste and Resources Action Programme (WRAP) has found that this could be costing families in the UK up to £700 a year. Many companies are realising that new methods of improving packaging can bring real commercial and societal benefits.

A multi-layered problem

For many food products packaging is structurally complex. Containers and covering materials can be made up of several layers, each serving a different purpose from barrier performance, tear resistance, and mechanical strength to aesthetics. Altering the production lines of such complicated product represents a large capital cost, acting as a barrier to research and development to explore new materials. However, although many basic plastic packaging products can be cheap and perform well, more specialist food containers are expensive to produce, and the industry is now looking for alternatives that reduce plastic use, if performance can be matched at lower prices.

Graphene could play a role in such applications as it has several properties that lend themselves well to food packaging. It can act as a barrier to oxygen and moisture, and features both conductivity for antistatic packaging and stiffness to strengthen packaging. In particular, graphene has the potential to help improve food packaging in three key areas.

1. Developing thinner and stronger materials – a simple way to reduce plastics in packaging is by achieving the same mechanical performance with decreased thickness. This could be done by applying ideas explored in nanocomposites to food packaging and using graphene’s high mechanical strength and barrier performance to enhance protection.
2. Creating selective barriers – although the main function of most food packaging is to act as a barrier to oxygen and moisture, some foods, such as meat and fruit products, need to be able to release gases during transport and storage. Holes in packaging are often used to allow fruit to release ethylene for example. In these cases a careful balance of permeation of the different gases may be required and 2D materials can be used to develop packaging with selective barriers that allow the permeation of some gases while blocking others.
3. Improving the barrier performance of biodegradables – many materials with good barrier performance exist, but they tend not to be biodegradable. Biodegradable plastics could potentially be improved with the addition of graphene to achieve high levels of barrier performance in a compostable product. In addition, outside of the food sector there are also possible applications where better biodegradable packaging could be important. One example is in India where products such as shampoo are often sold in single use sachets, the disposal of which is creating an environmental issue.

Applying the materials of the future

Graphene (and other 2D materials) have significant potential to help reduce the amount of plastics in packaging, or in providing competitive alternatives. The National Graphene Institute (NGI) in the University of Manchester currently has over 300 researchers looking at innovative new ways of using graphene in applications ranging from packaging to novel energy storage systems.

The Graphene Engineering Innovation Centre (GEIC) which opens later this year will also focus on pilot production and scale up of graphene and other 2D materials in packaging applications, and we are also working to help address other environmental challenges facing the country through initiatives such as “light-weighting” in electric vehicles. The NGI and GEIC are now actively seeking industrial and commercial partners for projects that have the potential to reduce the amount of plastics in packaging.

In addition, there is currently a significant government drive to improve productivity in the UK. If we can increase the intensity of R&D spend, and hence reduce the development time and cost of new products using novel materials such as graphene, we can start to address this challenge. In doing so, not only can the country’s productivity be improved, but we can also contribute to meeting the significant global environmental challenge highlighted so well in Blue Planet II.