Plastic can be programmed to have a lifespan of days, months or years

Chemical additives to plastic that mimic natural polymers such as DNA can create materials that break down in days, months or years rather than littering the environment for centuries. The researchers hope their new technology will lead to plastic products that will serve their purpose and then safely self-destruct.

In 2022, more than a quarter of a billion tons of plastic were thrown away worldwide, and only 14 percent was recycled – the rest was either burned or buried. The promise of practical, biodegradable plastic has been around for a long time. at least 35 years oldand there have been attempts to create such materials using everything that bamboo To seaweed. But in fact, many such materials difficult to compost and their manufacturers make unrealistic claims.

Now, Yuwei Gu and colleagues at Rutgers, The State University of New Jersey, are developing technology to create plastics with a precisely tuned lifespan that can quickly degrade either in compost or in the natural environment.

Gu wondered why natural long-chain polymers such as DNA and RNA could degrade relatively quickly while synthetic ones such as plastics could not, and whether there was a way to replicate this process.

Natural polymers contain chemical structures called adjacent groups that promote degradation. These structures drive internal reactions called nucleophilic attacks, which break bonds in polymer chains—something that requires a lot of energy in the case of conventional plastics.

Gu and his team created artificial chemical structures that mimic these neighboring groups and added them when making new plastics. They discovered that the resulting material could easily break down and that by changing the structure of the additives, they could fine-tune how long the material would remain intact before disassembling it.

Once the plastic breaks down, the long polymer chains turn into small fragments, which Gu hopes will either be used to make new plastics or dissolve safely into the environment.

“This strategy works best for plastics that benefit from controlled degradation over days or months, so we see great potential for applications such as food packaging and other non-durable consumer materials,” Gu says. “It is currently less suitable for plastics that need to remain stable for decades before breaking down, such as building materials or long-lasting structural components.”

But before this type of plastic can be used commercially, several issues need to be addressed. The liquid left behind when the plastic breaks down consists of fragments of polymer chains, and further testing is needed to ensure that this soup of parts is non-toxic and can therefore be safely released into nature.

Additionally, ultraviolet light is currently required to initiate destruction, although ambient sunlight is sufficient. So, until the team finds ways to create materials that can break down in the dark, any plastic that is buried or otherwise covered will remain in the environment almost indefinitely.