Polytetrafluoroethylene (PTFE) is one of those chemical innovations that has gone from wonder material to societal scourge. Better known by its brand name, Teflon, PTFE is remarkably unreactive and can withstand high temperatures, which makes it excellent for use in nonstick cookware, industrial and medical coatings, and electronic insulation and as seals and gaskets when using harsh chemicals—an early use of PTFE was to prevent uranium hexafluoride leaks during the Manhattan Project. But the same chemistry that makes PTFE durable also makes it a persistent pollutant when it winds up in landfills, where it resists decomposition for thousands of years.
In the past year, several research groups have reported methods for upcycling PTFE into useful chemicals. The latest work in this area comes from chemists led by Roly J. Armstrong at Newcastle University and Erli Luand Dominik J. Kubicki at the University of Birmingham. The team developed a process that transforms PTFE into sodium fluoride and amorphous carbon (J. Am. Chem. Soc. 2025, DOI: 10.1021/jacs.5c14052).
“We’re taking Teflon and turning it into a component of toothpaste,” Armstrong says.
The chemists use a ball mill to grind chunks of sodium metal together with PTFE in what’s known as a mechanochemical reaction. Because the reaction uses no solvents and has no by-products, it’s environmentally friendly and has 100% atom economy. Other PTFE-upcycling reactions that have been reported to date use organic solvents or complex catalysts, or they create by-products.
“Our chemistry is very simple,” Lu says. “We can make use of the carbon produced as activated carbon, and we can make use of the sodium fluoride.”
Norio Shibata, a chemist at the Nagoya Institute of Technology who reported a defluorination of PTFE using a sodium dispersion in solution earlier this year, says this work is a nice addition to the growing body of literature on upcycling fluorochemicals and fluoropolymers. Shibata tells C&EN that he worries about industry’s rush to phase out fluorinated materials. He says companies should be looking at the materials’ whole lifespan now that there are ways to upcycle and recycle those materials.
More complex products and scaling up beyond the ball mill
In addition to making sodium fluoride, the Newcastle and Birmingham researchers showed they can use the process to synthesize sulfonyl fluorides and acid fluorides by adding sulfonyl chloride and acid chloride acceptor molecules, respectively, into the ball mill.
Mark R. Crimmin, who works on recycling fluorocarbons at Imperial College London and was not involved in the project, says the reaction’s highly efficient conversion of PTFE to sodium fluoride is exciting.
But he adds that it’s not clear if that sodium fluoride will be broadly useful in other fluorination reactions. He says in an email that the limited scope of acceptor molecules reported in the paper and the use of additives to make the sulfonyl fluorides and acid fluorides “suggest that there are still some challenges to solve with this approach.”
“We’re trying to make every bit of this PTFE useful instead of just dumping it into the landfill.”
The use of sodium metal, which is air and moisture sensitive, might give some pause. But Lu says, “It’s not as bad as you may think.” The chemists do the reaction in a glove box under inert atmosphere, but they say that sodium metal can be used in air because there is a protective layer of oxides that forms on the metal’s surface. And because there’s no organic solvent involved, there’s no fuel for fire.
Véronique Gouverneur, a chemist at the University of Oxford who reported a mechanochemical process for upcycling PTFE with phosphate saltsearlier this year, says it’s encouraging to see other groups working toward a circular fluorine economy.
She says in an email that the new method “is concise, which is appealing, but the use of sodium poses challenges for larger scale operations.”
Lu says that using ball milling on an industrial scale is probably not practical, but the team is looking into other options, such as twin-screw extruders, for doing the reaction on a large scale.
There were more than 240,000 metric tons of PTFE produced worldwide in 2023, according to Market Reports World. Lu says, “We’re trying to make every bit of this PTFE useful instead of just dumping it into the landfill.”
Original article online at: https://cen.acs.org/materials/polymers/reaction-turns-teflon-toothpastes-key/103/web/2025/10