Two years ago, a research team from the U.S. Department of Energy and U.S. Lawrence Berkeley National Laboratory revealed their new plastic called poly(diketoenamine) or PDK. The material has all the convenient properties of traditional plastic, without harming the environment, and can be recycled indefinitely without any change in product quality.

Now, the team has studied how PDK could be commercially competitive and how manufacturers could use it on a large scale. Over time, PDK gets less expensive to produce and becomes more sustainable. PDK plastic readily breaks down when put in an acidic solution. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its look and feel.Source: Peter Christensen/ Berkeley Lab

The researchers simulated a 20,000 metric ton per year facility that would produce PDKs and take in PDK waste for recycling. The chemical inputs and technology needed, cost and greenhouse gas emissions of the project were determined and compared with equivalent figures in traditional plastic production.

To create PDK plastic, a resin polymer was engineered to easily break down into individual monomers when mixed with acid. These monomers can be separated from additives and gathered to make new plastics without losing any quality. Earlier research found that PDK's chemical recycling process does not use a lot of energy and has low carbon dioxide emissions, potentially offering a circular life cycle for the plastic.

The team says the best initial applications for PDK would be in markets where a company receives the product back at the end of its lifespan, like the auto industry or consumer electronics. In these fields, thanks to buybacks, trade-ins and consumer returns, the customer would return the product to be recycled when they are done with it. By participating in this process, companies would receive sustainable branding and long-term savings. After starting in these initial industries, the team wants to expand to shower lived, single-use goods like the packaging.

The cost of recycled PDK is already projected to be competitively low. The team is working on additional refinements to lower the cost of virgin PDK and to design a production process for PDK polymers using microbe precursor ingredients. Currently, the process uses industrial chemicals.

Collaborators from the International Institute for Applied Systems Analysis (Austria), University of California Berkeley, Technical University of Denmark and Shenzhen Institutes for Advanced Technologies (China) also contributed to this research, which is published in Science Advances.