United States: Virginia Tech University researchers have discovered a new method to convert old plastic into soap. The research was published in the academic journal Science. Plastics can now be transformed into high-value chemicals known as surfactants, which are used to create soap, detergent, and more.
Mr. Guoliang Liu, an associate professor of chemistry at Virginia Tech and author of the paper, has suggested that it should be possible to convert polyethylene into fatty acids and then into soap. The challenge was how to break a long polyethylene chain into many short chains and how to do it efficiently, as per the report. Mr. Liu believed there was potential for a new upcycling method that could take the low-value plastic waste and turn it into a high-value, useful commodity.
In winter, near a fireplace, Mr. Liu watched the smoke rise from the fire and thought about how the smoke was made up of tiny particles produced during the wood’s combustion. The researcher decided to burn polyethylene in a safe laboratory setting.
Firewood is mostly made of polymers such as cellulose. The combustion of firewood breaks these polymers into short chains and then into small gaseous molecules before full oxidation to carbon dioxide. If we similarly break down the synthetic polyethylene molecules but stop the process before they break all the way down to small gaseous molecules, then we should obtain short-chain, polyethylene-like molecules.
Mr. Liu said.
The author and his team constructed a reactor resembling an oven, designed for the secure combustion of plastic materials. The lower section maintained a high temperature to effectively break down polymer chains, while the upper part was cooled to prevent excessive degradation.
After gathering the leftover material, the researchers discovered they had produced a substance identified as short-chain polyethylene, which resembles wax. Subsequently, they proceeded to convert this wax into soap.
“It’s the first soap ever made from plastic in the world. It has a bit of a unique colour. But it works,” the associate professor stated.
Researchers from the Department of Chemical Engineering were also part of this project and the resulting research paper, as per the statement.
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