Achieving Electrifying Progress in Creating Sustainable Polymers

Chemistry researchers at Flinders University have made their “gold discovery” by discovering a new way to make “green” polymers from low-cost building blocks with a small amount of electricity.

The reaction is rapid and takes place at room temperature. No hazardous chemicals needed — just electricity, with many potential uses including in gold mining and e-waste recycling, a multidisciplinary team reveals in an article just published in Journal of the American Chemical Society.

While hundreds of millions of tons of plastic are produced each year, with up to half used for individual purposes, the Flinders University research group is working on more sustainable options. The energy used in production contributes to pollution and global warming.

says co-author Dr. Thomas Nicholls, an expert in using electrochemistry to make valuable molecules.

The process begins with adding an electron to the basic building block or monomer. After the monomer is “electrocuted”, it reacts with another building block in a chain reaction that leads to the formation of a polymer.

First author and Ph.D. Candidate Yasmin Poppel says, “Our method of producing electrochemical polymers provides new, high-performance, environmentally friendly materials.”

“The use of electricity to make valuable molecules is rapidly expanding due to its versatility. In addition, it may generate less waste than conventional chemical syntheses and can be powered by renewable energy.”

The main polymer the team made contains sulfur bonds in the backbone. These sulfur groups can do useful things like bind to precious metals like gold. The team showed that the lead polymer can remove 97% of gold from solutions related to mining and e-waste recycling.

Sulfur-sulfur bonds can also be broken and repaired. This intriguing property enabled the team to discover the conditions for returning the polymer to its original building block. This is an important advance in recycling.

Typically, when common plastics are recycled, they are simply heated and reshaped into a new product. This process can cause degradation and downcycling (conversion to a less valuable material), leading to eventual disposal in a landfill.

In contrast, the polymers made in the Flinders University scientists’ latest research can be chemically converted into their constituent building blocks in high yield – meaning that building block can be used again to make new polymers.

The team also performed quantum mechanics calculations to understand the details of how the interaction works. The results were surprising and fortuitous.

Says research associate in computational and physical chemistry d.

Future applications for this class of materials include environmental remediation, gold mining, and the use of the polymer as an antimicrobial agent.