Researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory have designed a new kind of plastic polymer that can be broken down and built up again with the simplicity of a molecular Lego brick.
“Most plastics were never made to be recycled,” says chemist Peter Christensen. “But we have discovered a new way to assemble plastics that takes recycling into consideration from a molecular perspective.”
That stringy web of molecules can be mixed with a wide variety of chemicals, giving plastics diverse properties that allow us to use them for just about anything from shopping bags to clothing, to straws, and furniture.
Many plastics suffer from those additives that cling to the molecular chains to colour, soften, or harden them, making for an unpredictable mess of ingredients to convert into a durable product we can easily afford.
By breaking the polymers down easily, the plastic’s core units can be separated from any additives over and over again in what is described as a closed-loop cycle.
The researchers tested the recovery process by contaminating PDK and acid solutions with other substances, including fibreglass and flame-retardant chemicals, finding the additives had little impact on their diketoenamine harvest.
The end result is a plastic ingredient that can shake off any colours or strengthening agents in several easy steps to be turned back into another product.
“We’re interested in the chemistry that redirects plastic lifecycles from linear to circular,” said Helms. “We see an opportunity to make a difference for where there are no recycling options.”
Further research is needed to test the polymer’s suitability for various applications. Nobody wants a bendy plastic knife or a brittle shopping bag, no matter how recyclable it is.
But whatever the results, this is what the future of plastics looks like and we need it urgently.