'Infinitely' Recyclable Polymer Could Be the Future of Plastics

A lab at Colorado State University has developed a completely recyclable polymer, pictured here. Bill Cotton/Colorado State University

Plastic is easy, convenient, cheap and long-lasting. But the same traits that make plastic appealing have also made it a scourge to the environment.

Since plastic entered mass production, scientists estimate that 8 billion tons have been produced — and we aren't very good at recycling. By 2015, 6,945 tons — or about half the weight of the Brooklyn Bridge — of plastic waste had been generated, with around 9 percent of it getting recycled. About 79 percent of it ends up in landfills or scattered around the environment, including the ocean. We may end up drowning in plastic before long.

Chemists at Colorado State University think they've found a solution, however. They've discovered a polymer that has many of the properties of plastic — it's light, strong, durable and heat-resistant — but that "can be converted back to its original small-molecule state for complete chemical recyclability," according to a statement released by the university. Even after being recycled, the substance can be turned back into its plastic-like state, and this can be done quickly and cheaply.

Breaking down plastics

Plastic waste waiting to be recycled
Recycling plastic isn't easy or all that efficient. photka/Shutterstock

The recycling process for plastic bottles isn't always quick and easy, and some plastics can't be recycled at all. The difference comes down to polymers and how they respond to heat. Thermoplastics, for instance, don't handle heat super well because no chemical bonding took place in the formation process to allow them to maintain a set shape. This makes recycling and reusing them for other products relatively easy. Thermoset plastics, as you might have guessed, are the opposite. Strong bonds between the polymers form, resulting in a plastic that maintains its shape even under intense heat. This makes such plastics unrecyclable.

Even thermoplastics often are not reused or recycled for a host of reasons, from contamination from dyes to the fact that some companies would rather create virgin plastics instead of incorporating recycled plastics into their manufacturing. When you factor in the time, energy and cost required to melt and turn the thermoplastics into pellets that can be reused to create something else, the value of recycling — while obviously useful and important to the overall state of the environment — is weighed by the scales of capitalism.

Plastic pellets after the recycling practice
These plastic pellets will be something else soon. Hopefully. diak/Shutterstock

The polymer developed at Colorado State could potentially tip those scales.

As outlined in a study published in Science, this new polymer was first discovered in 2015, but it took the chemists some time to develop one that was similar enough to plastics to be commercially useful and environmentally sound, meaning it was easy and cheap to recycle and could be used over and over again.

What they developed was a polymer that maintains all the good qualities of plastics yet is relatively easy to manufacture and to recycle. Making it requires room-temperature conditions, a short reaction time to bond the monomer into polymers and only a small amount of the catalyst remains in the end product. It has a high molecular weight, stands up to heat and generally behaves like plastic.

Recycling it requires similarly little effort. "Mild lab conditions" are required and so is a catalyst. Once applied, the polymers are once again monomers in a matter of minutes and can be used to create another product, no further purification required.

"The polymers can be chemically recycled and reused, in principle, infinitely," Eugene Chen, a chemistry professor at Colorado State and lead author of the study, said in the statement.

But don't get too excited about this just yet. Chen stressed that the polymer and the process isn't ready for commercial products just yet. There's still plenty of development to do, including making it more cost-efficient to produce and recycle, both on the chemical and logistical levels.