Scientists Create a Plastic That Can Be Recycled Endlessly

Plastic is here to stay. It takes 400 years to degrade but up to 91% of plastic is not being recycled., according to National Geographic. Compounding the issue is that not all plastic is recyclable.

Researchers at the US Department of Energy's Lawrence Berkeley National Laboratory set out to address this issue at a molecular level by designing a new type of plastic that can be recycled endlessly. Think of it like a Lego playset- the plastic can be disassembled at the molecular level, and then reassembled again and again into a different shape, texture, and color without losing quality or performance.

Currently all plastics are made up of large molecules called polymers, which in turn are made up of shorter carbon-containing compounds called monomers. The problem is that the harsh chemicals added to plastic to make them tougher or more flexible are bound tightly to these monomers and wind up staying in the plastic long after it has been processed at a recycling plant.

When plastics are processed at such plants, they are all thrown into the mix together, regardless of their chemical compositions, making it difficult to predict which properties will feature in the new material that they were melted together to form. This has made it impossible to create a material that can be reused repeatedly, or "upcycled" to form a better-quality product.

This is where PDK plastic comes in. The monomers of this new material, created by researchers and reported in the journal Nature Chemistry, can be freed from other compounded additives by dunking it into a highly acidic solution. Ultimately this separates the monomers from the chemical additives that give plastic its look and feel.

"With PDKs, the immutable bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively," said team leader Brett Helms. "We’re at a critical point where we need to think about the infrastructure needed to modernize recycling facilities for future waste sorting and processing."

Helms noted that, if facilities were designed to recycle or upcycle PDK, it would be easier to divert plastic from landfills and the oceans.

"This is an exciting time to start thinking about how to design both materials and recycling facilities to enable circular plastics," he said.

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