Recycled plastic bottle research outlines significant environmental benefits

Scientists at Edinburgh’s Heriot-Watt University have won funding from Innovate UK to develop additives and processing methods that could significantly increase the amount of recycled material that can be used.

It is hoped the work – being carried out along with Glasgow-based business Enviropet and scientists from the University of Strathclyde – will help companies meet UK and European requirements for all new PET (polyethylene terephthalate) bottles to contain a minimum of 30 per cent recycled material from 2030.

While more than 580 billion PET bottles are produced each year, most of these contain little or no recycled materials. Drinks companies claim this is because variations in the recycled plastic can affect the colour and clarity of the finished product and can also lead to bottle failures which could see fizzy drinks go flat.

Professor David Bucknall of Heriot-Watt University said: “We want to solve the problems faced by using more recycled PET content in plastic bottles, which currently results in significantly poorer-quality bottles in terms of their mechanical properties and appearance.

“We’ll be testing how the additive improves the performance of recycled PET blends in a number of critical properties that directly affect the PET bottle behaviour. We will measure gas permeability through the plastic, which has a direct impact on the product shelf-life.

“To have a long shelf-life the plastic must prevent oxygen permeating into the bottle and affecting its content, but also stop CO2 escaping so that carbonated drinks don’t go ‘flat’.

“Our colleagues at the University of Strathclyde will integrate artificial intelligence and deep learning to ensure that the appropriate amount of additive will be included during melt processing of the PET mixtures.

“This will help manufacturers to use this system so that the correct blend ratios and processing conditions are automatically maintained to produce consistently predictable products.”

He added: “This project is exciting because we may be able to exceed 30 per cent recycled material in any PET bottle, which would have significant long-term environmental benefits.”

Douglas Craig, managing director of Enviropet, said: “Our technology will help manufacturers comply with recycling targets and legislation and improve their bottle quality and environmental performance.

“It could potentially save firms millions by reducing the amount of raw material needed for new bottles, as well as the energy resource required for their manufacture. All of the major PET bottle manufacturers have outlets in the UK, which means we have a gateway to a global market.”

Plastic waste and pollution is a pressing global concern. According to a report released in October last year, plastics are on track to contribute more climate change emissions than coal plants by 2030.

An investigation by E&T this month revealed that UK supermarkets are becoming entangled in the murky world of plastic waste recycling, highlighting a shortfall between good intentions and real-word results.

However, there is also positive movement around tackling plastic pollution. In January this year, researchers from Aarhus University demonstrated for the first time a computer vision technology that can be used to differentiate between a wide range of plastics according to their chemical composition. Applied on an industrial scale, this could enormously increase the rate of plastic recycling.

Further research into improving the rate of recycling for plastics was announced earlier this month, with a research team from the University of Birmingham showing a new process for recycling mixed plastic packaging which delivers a greater proportion of high-value recycled plastic with less emissions and no solvent residues.

In October 2021, scientists at the Tokyo Institute of Technology unveiled bio-based polymers which could be transformed into fertiliser using a pioneering circular system, effectively enabling the bioplastics to be chemically recycled back into fertilisers and ploughed into the soil.

In a direct consumer-related move, Dubai announced this month that it would introduce a charge for plastic bags in shops, promising a total ban within two years. A signficant number of sea turtle and camel deaths in and around the Emirate of Dubai capital city are directly linked to the ingestion of plastic carrier bags.