In a perfect world, plastic would never be on a trip to the landfill, it is a vision that we have strived to achieve for decades. Unfortunately, some plastics simply do not recycle as easily as others, which limits how well we can reuse them in new products. But a new type of plastic could help change all that.
Researchers at the Lawrence Berkeley National Laboratory of the US Department of Energy. UU They have designed a new type of plastic polymer that can be decomposed and rebuilt 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 of badembling plastics that takes recycling into account from a molecular perspective."
All plastics are more or less repetitive units, or monomers, of compounds derived from an organic substance such as petroleum.
This dense network of molecules can be mixed with a wide variety of chemical products, which gives plastics various properties that allow us to use them for almost anything, from shopping bags to clothing, straws and furniture.
For the eternal confusion of consumers everywhere, some of these plastics can be broken down into components and recycled relatively easily. But not all. We could throw our polyethylene terephthalate (PET) bottles in the recycling bin, but not a sturdy and thermostable plastic toy or utensil.
Many plastics suffer from those additives that adhere to the molecular chains to color, soften or harden them, which makes an unpredictable disorder of ingredients become a durable product that we can easily buy.
Researchers have made some progress in redesigning thermoset plastics to become recyclable, but to really solve our growing plastics crisis, we need the process to be as efficient and simple as possible, and the new type of plastic developed in the laboratory. Berkeley has the potential to meet such demands
Its building block is a monomer called diketoenamine: a compound formed by the adhesion of a tricetone to an amine.
By condensing these units on a long rope, a plastic called poly (diketoenamine) or PDK is formed, and the bonds can be easily dissolved using nothing more than a 12-hour bath in a strong acid bath.
"With the PDK, the immutable links of conventional plastics are replaced with reversible links that allow the plastic to be recycled more effectively," says chemist and team leader Brett Helms.
By decomposing the polymers easily, the central units of the plastic can be separated from any additive again and again in what is described as a closed cycle cycle.
The researchers tested the recovery process by contaminating PDK and acid solutions with other substances, such as fiberglbad and flame retardant chemicals, and found that the additives had little impact on their diketoenamine crop.
The end result is a plastic ingredient that can shake any color or strengthening agent in several easy steps to turn it back into another product.
"We are interested in chemistry that redirects the life cycles of plastic from linear to circular," said Helms.
"We see the opportunity to make a difference where there are no recycling options."
At this time, most of our recycling efforts are abysmal. While some countries are doing everything possible, countries like the United States barely manage to recycle a quarter of their PET waste.
Governments can always do their part to enforce the action, but at the end of the day, money talks. Earlier this year, the researchers demonstrated how we could turn plastic into a much more lucrative resource: fuel.
It is worth investigating any method we can find to facilitate recycling for the consumer and appeal to the manufacturer.
Of course, we are far from shipping our PDK forks to an acid tank at our local recycling plant. More research is needed to test the suitability of the polymer for various applications. No one wants a flexible plastic knife or a crisp shopping bag, no matter how recyclable.
But whatever the results, this is the future of plastics and we urgently need it.
This research was published in Chemistry of nature.