NEWS: Bio-plastic 'breakthrough'

Scientists have developed a new way to break down plant-based plastics - allowing them to be 'recycled repeatedly without a loss in the quality of the plastic'.

At the moment they can't be continuously recycled into new drinks bottles and are often reused for lower grade products such as water pipes, park benches or traffic cones.

The team from the Universities of Bath and Birmingham say by converting plastics back into their constituent chemical molecules they can make new plastics of the same quality as the original.

The researchers looked at recycled plant-based PLA, which is made from starch or crop waste instead of petrochemicals - and is used in biodegradable food packaging and disposable cutlery and cups.

PLA isn’t currently recycled because it's not widely used but the team suggest: "With growing awareness of plastic pollution, the demand from consumers for recyclable packaging is growing."

Around 45 per cent of plastic waste is recycled annually in the UK, something which is increasing.

The team’s method, published in ChemSusChem, uses lower temperatures and more environmentally-friendly catalysts than previous methods.

Professor Matthew Jones, from the Centre for Sustainable & Circular Technologies at the University of Bath, said: "Most plastic is currently recycled using mechanical methods, where they are chipped into granules and melted down before being moulded into something new.

"The problem is, melting plastic changes its properties, and reduces the quality, which limits the range of products in which it can be used.

"Our method of chemical recycling overcomes this problem by breaking down plastic polymers into their chemical building blocks, so they can be used all over again to make virgin plastic without losing any properties."

The team has also started trialling a similar process for recycling PET, which is used for drinks bottles.

First author of the paper Dr Paul McKeown from the University of Bath, said: "PLA is being increasingly used as a sustainable alternative for single-use plastics.

"Whilst it's biodegradable under industrial conditions, it doesn’t biodegrade with home composting, and isn’t currently recycled, so at the moment it commonly ends up contributing to the tonnes of plastic waste in landfill and oceans.

"There is no single solution to the problem of plastic waste - the approach has to be a combination of reducing, reusing and recycling.

"Our method of chemical recycling could allow carbon to be recycled indefinitely - creating a circular economy rather than digging more up from the ground in the form of fossil fuels, or releasing it into the atmosphere as a greenhouse gas."

So far, the technology has only been demonstrated on a small scale.

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