Why We Are Still Waiting on Endlessly Recyclable Plastics


A team of research scientists at the Berkeley National Lab came up with a new kind of plastic known as polydiketoenamine (PDK) back in 2019. PDK is revolutionary in a number of ways. Among them is the fact that it can, at least in theory, be recycled endlessly. Knowing what we know about plastic recycling, why hasn’t PDK taken the world by storm as of yet?

It is not unusual for scientific breakthroughs to take years to catch on. Thus, no one is surprised that PDK still hasn’t gone much beyond Berkeley. If it ever does, researchers say it could replace petroleum-based plastics for nearly every application. PDK plastics could be endlessly recycled, thus greatly reducing the need to produce virgin plastic.

It’s All About the Monomers

Plastic are polymers made up of individual monomers that are bonded together. Breaking down a plastic into its base components requires breaking the bonds. This is not as easy as it might sound. There are chemical processes for doing so, but they almost always result in a loss of performance.

Tennessee-Based Seraphim Plastics, a company that offers industrial plastic recycling in seven states, says that the difficulty in separating monomers explains why most plastic recycling is mechanical rather than chemical. Seraphim buys industrial plastic, turns it into regrind, and then sells it to companies that mix it with version plastic.

One of the things that makes PDK different is the ease by which bonds between monomers can be broken. According to the Berkeley Lab scientists, PDK monomers can be easily broken without any loss of performance. Recovered materials can then be easily separated and used to make new materials.

A Lack of Infrastructure

Let us assume for one minute that PDK is everything the scientists say it is. In fact, let’s say it’s even better than advertised. It still has a long way to go before being commercially viable. The biggest hurdle right now is a lack of infrastructure. You need infrastructure to produce PDK, turn it into commercial and consumer products, and recycle it at end-of-life.

That infrastructure just doesn’t exist. Moreover, building it would take a significant amount of time and cost a lot of money. Are there companies willing to invest the time and money? To date, interest hasn’t been extremely high.

Petroleum Plastics Are Cheap

It would seem as though PDK is a game-changer that could make a ton of money for any company willing to invest. So why are companies reluctant? There are a couple of reasons, beginning with the fact that petroleum-based plastics are so cheap. Companies are not paying a whole lot for virgin plastic. Regrind makes it even cheaper by way of supplementation.

What it really boils down to is demand. In that sense, PDK is a lot like the original electronic cigarette first introduced in the 1960s. Back then, its inventor could not convince cigarette manufacturers to embrace it because people still wanted tobacco. It wasn’t until the early 2000s that there was a real market for e-cigarettes.

Much of what scientists believe about PDK as a replacement of petroleum-based plastics is speculation. PDK is still too new and unproven to definitively say it is superior to other plastics in every way. And quite frankly, the laws of physics dictate that nothing can be endlessly recycled without loss of integrity. There is always some loss, even if it is minuscule.

Until PDK has a lot more science behind it, companies are not going to invest in building the infrastructure necessary to utilize it. That’s why PDK remains mainly a research project right now.

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