Under pressure on all fronts, fluoropolymer makers are struggling to transform their industry into a more sustainable business.
In February, the European Chemicals Agency published a proposal from five member countries to ban per- and polyfluoroalkyl substances (PFAS) containing at least one fully fluorinated carbon atom—an estimated 10,000 molecules in all, including popular fluoropolymers. Member states would vote on a ban in 2025; if it’s enacted, exceptions for fluorinated chemicals that cannot be replaced with alternative chemistries would expire in 7–12 years.
In the US, the Environmental Protection Agency is working on mandatory drinking-water limits on PFAS molecules. State sanctions on PFAS are more far reaching, and many states have implemented restrictions on these so-called forever chemicals in applications including cookware, cosmetics, firefighting foam, textiles, and packaging.
The private sector is also voluntarily shunning this class of chemicals. For example, McDonald’s, Starbucks, and Chick-fil-A are eliminating PFAS from food packaging. Investment firms, which see PFAS as a liability, have called on chemical makers to phase them out. And chemical companies face billions of dollars in liabilities related to PFAS contamination.
In December 2022, 3M declared that it had had enough. Pointing to increasingly stringent regulations as well as customer demand for alternatives, the maker of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and other fluorinated polymers said it would walk away from the entire business—which generates annual sales of about $1.3 billion—by 2025.
“The challenges of managing businesses and operations with products based on PFAS have increasingly weighed on our business results in recent years,” 3M said at the time. Last year, for example, the company signed an agreement with the Flemish government to start a $600 million remediation program at its site in Belgium.
But 3M’s rivals don’t plan to follow it out the door. They have an alternative strategy that they hope will allow them to preserve their businesses over the long run. These firms make a distinction between fluoropolymers, which they say are nontoxic and pose no health risk, and the fluorosurfactants used to make them. Some of those chemicals, such as perfluorooctanoic acid (PFOA), have been demonstrated to bioaccumulate and are detrimental to human health and the environment. The companies have ramped up R&D in nonfluorinated alternatives. And where they can’t find new surfactants, they aim to mitigate fluorosurfactant emissions.
The European proposal, if it stands unchanged, would spell the eventual end for common fluoropolymers like PTFE and PVDF. “They are absolutely in the scope of the current European definition of PFAS,” says Amber Wellman, director of sustainability for Chemours’s advanced performance materials business, a major fluoropolymer producer. But regulators shouldn’t be targeting the fluoropolymers themselves, she says. “They’re inert. They’re high-molecular-weight polymers. They’re not mobile. They’re not bioavailable. They don’t bioaccumulate.”
In a recent statement, Arkema, another fluoropolymer maker, said that fluoropolymers made without fluorosurfactants ought to be exempted from the proposed European regulations.
Mike Finelli, Solvay’s chief North American officer, acknowledges that some PFAS molecules have issues with persistence and bioaccumulation. “That’s the fluorosurfactants, and they’re problematic,” he says. “So our approach and our motivation is, let’s fix the problem. Let’s get out of these surfactants to make sure that the polymers, which are safe and sustainable, will be around for a long time, because they bring tremendous value to the world.”
Fluoropolymers have elite properties. They are resistant to chemicals and extreme temperatures—reasons they are used widely in the aerospace industry. And they often impart lubricity at their “nonstick” surfaces.
Officials at fluoropolymer companies are quick to point out clean energy and high-tech sectors that couldn’t manage without the polymers. “Fluoropolymers are the key membrane that splits H2O into H and O,” Finelli says. “That’s how you make green hydrogen. And in a fuel cell, that same fluoropolymer recombines the hydrogen with oxygen to generate electricity.”
Frenk Hulsebosch, Chemours’s global technical director for advanced performance materials, points to the perfluoroalkyloxy alkane (PFA) copolymer tubes and fittings that semiconductor fabricators use to carry aggressive and high-purity fluids like hydrofluoric acid. “You need the chemical inertness, and you need the purity for these semiconductor chips,” he says.
But ever since fluoropolymers were introduced, in the middle of the 20th century, making many of them has required using fluorosurfactants. These processing aids are critical to the emulsion polymerization process, in which a polymer is built in water from fluorinated monomers.
“The surfactant stabilizes the growing emulsion particle during polymerization, so you don’t get agglomeration or coagulation,” explains Scott Gaboury, chief science officer at the fluorochemical consulting firm Cogmium. When the polymerization is done, the surfactant is washed out of the polymer mixture, but some residual surfactant remains. Fluorosurfactants have minimal impact on the polymer’s final properties, he says.
The fluoropolymer industry has changed the fluorosurfactants it uses as polymerization aids before. In the 2000s, the long-chain surfactant PFOA, which has been linked to detrimental effects on human health, was turning up near DuPont’s (now Chemours’s) plant near Parkersburg, West Virginia.
In 2006, the EPA launched the PFOA Stewardship Program, which aimed to eliminate the compound by 2015. The major fluoropolymer makers that signed onto the initiative replaced PFOA with shorter-chain alternatives that were thought to be less bioaccumulative because they are more water soluble. For example, 3M switched to ADONA, an ammonium salt of 4,8-dioxa-3H-perfluorononanoic acid. DuPont completed a transition to its GenX technology, which is based on hexafluoropropylene oxide dimer acid, in 2013.
But some of these replacements have now been detected in the environment, and a regulatory and consumer backlash has been mounted against PFAS. Fluoropolymer makers are taking the next step and trying to get out of fluorosurfactants altogether.
The task is trickier than merely swapping one fluorinated surfactant for another, Gaboury says. “It’s relatively easy to make the emulsion polymer with a nonfluorinated surfactant,” he says. “It’s difficult to make products with a nonfluorinated surfactant that have the same performance profile at the very end.”
Gaboury explains that when chemists change to a nonfluorinated surfactant, they usually change other ingredients as well, such as the initiator and the transfer agent. “You have a little bit different profile of reactor materials, and ultimately there’s a little bit different residual profile in the product.” That can cause performance problems, he says.
Chemours’s Wellman adds that the new surfactants are typically hydrocarbon-based. But the hydrogen-carbon bond isn’t as strong as the fluorine-carbon bond. “The presence of that hydrogen results in side reactions that you don’t want when you’re making a fluoropolymer,” she says. “That creates residuals that you also don’t want.”
Tackling these challenges has been a priority for fluoropolymer makers in recent years. Solvay, for instance, wants to phase out fluorosurfactants by 2026. In 2019, it quadrupled R&D spending on nonfluorinated polymerization technology and now has over 100 scientists dedicated to the effort. “You’re talking about replacing a chemistry that’s been around for 60, 70, 80 years,” Finelli says.
The company has racked up some successes. In June 2021, it stopped using fluorosurfactants to produce PVDF at its plant in West Deptford, New Jersey.
Finelli says the main breakthrough was modifying the process conditions in the reactor. Solvay won’t disclose which molecule replaced the fluorinated surfactant, but he says it is a nonfluorinated material that has been used “widely in many industries for many, many decades.”
The PVDF that Solvay made using the modified process had to be tested with clients. “At almost every customer, we had success,” Finelli says, adding that a few customers had to make some processing changes to use the modified polymer.
Although Solvay is one of the world’s largest PVDF producers, the plant in New Jersey was the only one it had to convert. Finelli says that about 90% of the company’s PVDF output uses a suspension process that doesn’t require fluorinated surfactants. Products made using that process tend to go into higher-end applications, such as batteries. For example, the $850 million plant that Solvay plans to build in Georgia with the fluorine supplier Orbia will use the suspension process. Emulsion PVDF tends to go into applications like coatings.
Another success for Solvay was sunsetting the fluorinated surfactants used to make its Tecnoflon HS FKM fluoroelastomers, found in applications such as gaskets and seals. The company aims to convert its Aquivion lines, used in fuel cell and electrolysis membranes, by 2026.
Arkema, one of Solvay’s chief PVDF rivals, uses no fluorosurfactants in the US and plans to phase them out globally by the end of 2024. Gaboury, a former scientist with the company, says Arkema is “an early example of a company looking at a nonfluorinated alternative.” It introduced Kynar 500 FSF, a line of PVDF polymers made with nonfluorinated surfactants, in 2008, when most of the industry was just beginning to convert from one fluorosurfactant to another.
Much of Chemours’s Viton FKM fluoroelastomer line has been made without fluorosurfactants for about 20 years, Hulsebosch says. The firm still used the processing aids for some grades with a more sophisticated polymer architecture, but last year it managed to switch these polymers as well. Hulsebosch says the trick was selecting the right hydrocarbon surfactant and running the polymerization to minimize the number of unintended fluorinated by-products generated.
But finding fluorosurfactant replacements is harder for some fluoropolymers than it is for others. For example, Hulsebosch says, PTFE is made with a highly reactive monomer, tetrafluoroethylene, that creates many unintended fluorinated by-products. He says Chemours hasn’t found fluorosurfactant alternatives for PTFE or for similar polymers such as fluorinated ethylene propylene and PFA copolymers that don’t result in such by-products.
Solvay has encountered similar problems, according to Finelli. “The higher the molecular weight, the higher the fluorine content, the harder the challenge,” he says. “That’s why, when we looked at our portfolio, we had a road map for almost everything but PTFE and high-fluorine PFA—these polymers in our mind would have taken too long.”
So, Solvay will stop producing them by midyear. Finelli says the company is a “tiny player” in PTFE, representing less than 2% of the world’s production capacity.
Some firms are claiming success with the problematic polymers. India’s Gujarat Fluorochemicals announced in November 2022 that it has developed a nonfluorinated polymerization aid for its PTFE and PFA products. It will revamp production of these polymers later this year. Gujarat says that with this development, it will be able to make its entire product line without fluorosurfactants.
For Chemours’s Teflon PTFE and other product lines for which the firm hasn’t found an alternative surfactant, it has favored a strategy of abating the fluorosurfactant emissions and thermally destroying the rest. “A nonfluorinated surfactant is not the ultimate solution,” Wellman says.
Solvay has a similar policy for one of its product lines. The company has not found an alternative surfactant for its Tecnoflon PFR polymer, so it is making it in a clean room environment and sequestering aqueous emissions from the process.
But even with surfactant switching and abatement, fluoropolymer makers may be looking at a market in retreat over the long run.
When manufacturers of consumer products can replace fluorinated materials, they will, rather than face potential bans or public backlash, says Bhushan Deshpande, vice president of technology at Techmer PM, which engineers custom formulations of plastics. “There is some desire not to have fluorine, to not have to worry about questions like this,” he says.
An example of how such substitutions are playing out comes from Techmer’s own portfolio. For decades, fluoroelastomers were blended into linear low-density polyethylene at concentrations of hundreds of parts per million. The elastomer lubricates the hot plastic as it runs through a film extruder, preventing melt fracture, which can give film an unsightly “shark skin” appearance. In January, Techmer launched HiTerra T5, a nonfluorinated lubricant; the firm says the chemistry is proprietary.
Fluoropolymer makers say they are anticipating this kind of substitution. Solvay itself has exited markets where fluoropolymers aren’t essential. For example, “you don’t need fluoromaterials for cosmetics,” Finelli says. “They bring value, but there’s other things.”
But in markets where fluoropolymers can’t be replaced, such as the green energy applications touted as contributing to a low-carbon future, Solvay wants to ensure as small an environmental footprint as possible. “Fluoropolymers are part of the solution,” Finelli says, “and we want to make sure they are around for a long time.”