PFAS and Polymer AM — Part 1

Per- and polyfluoroalkyl substances (PFAS) have a trifecta of qualities that make them the perfect bogeyman: potentially damaging, nearly ubiquitous and virtually immortal. It is little wonder that regulatory bodies, governments and supra-national organisations are increasingly keen to bring them under control.

Polymer AM is squarely in the mix here, both in ways that are obvious (materials that explicitly contain PFAS) and it carries risks that are harder to qualify and quantify (e.g., from un-reported PFAS, contamination or ancillary systems).

PFAS are both deeply embedded in industrial supply chains and, in many cases, technically difficult to replace. This series will explore how PFAS enter the polymer AM process chain, what the regulatory implications actually are and what mitigation strategies may be available to polymer AM stakeholders.

That includes materials suppliers, compounders, machine OEMs, AM part producers and, critically, end users who may inherit regulatory or reputational exposure without ever intentionally specifying PFAS-containing materials.

What are PFAS?

Specifically, OECD offers the following: "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e., with a few noted exceptions, any chemical with at least a perfluorinated methyl group (−CF3) or a perfluorinated methylene group (−CF2−) is a PFAS."

The “noted exceptions” refer to a carbon atom with a H/Cl/Br/I atom attached to it, such as Chlorotrifluoromethane (CF3Cl) and bromotrifluoromethane (CF3Br).

Depending on the specific molecular makeup, the thousands of individual compounds that are 'PFAS' exhibit a range of properties including chemical and thermal resistance, extremely low surface energy, hydro- and oleophobic behaviour, electrical insulation stability and highly consistent processing behaviour.

These same properties explain both their ubiquity and the difficulty regulators face in addressing them. Like polymers themselves, PFAS are not inherently “good” or “bad”; they are simply tools that happen to help solve a vast number of engineering and manufacturing problems. The challenge is their persistence, the scale of their use and their ability to move from where we want them to where we don't.

Over time, PFAS released from industrial processes can enter waterways, move into the food chain and accumulate across biological and ecological systems. While there are significant differences in bioaccumulation and biomagnification across compounds and ecosystems, the perception of humans as being 'at the top of the food chain', reinforced by some click-baity headlines, helps elicit the understandably visceral response against which regulatory attention has intensified.

Is this a today problem?

AM does intersect with PFAS in several ways: through feedstocks, additives, processing aids, coatings and downstream applications. As regulation increasingly focuses on entire process chains rather than individual products, AM can find itself implicated even where PFAS are peripheral rather than central.

Because there are so many different PFAS with different use cases and properties, there isn't sufficient data on their behaviour 'in the wild'. That includes where they end up and what biological or ecological effects they have when they get there. The US Environmental Protection Agency states:

Current scientific research suggests that exposure to certain PFAS may lead to adverse health outcomes. However, research is still ongoing to determine how different levels of exposure to different PFAS can lead to a variety of health effects. Research is also underway to better understand the health effects associated with low levels of exposure to PFAS over long periods of time, especially in children.

Current peer-reviewed scientific studies have shown that exposure to certain levels of PFAS may lead to:
- Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women.
- Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations, or behavioral changes.
- Increased risk of some cancers, including prostate, kidney, and testicular cancers.
- Reduced ability of the body’s immune system to fight infections, including reduced vaccine response.
- Interference with the body’s natural hormones.
- Increased cholesterol levels and/or risk of obesity.

There is need for more research, more data. And there is a need to understand where responsibility realistically sits, what commercial and regulatory risk looks like in the real world and how the industry can respond without resorting to superficial “PFAS-free” claims that satisfy neither regulators nor engineers.

The series begins in earnest in part two with a look at the regulatory backdrop, specifically the EU's REACH regulations. After that we'll see where PFAS really intersect with polymer AM, a deeper look at the risk landscape, exploring what regulations mean for different stakeholders, mitigation or substitution strategies and some real-world examples of how organisations are wrestling with the challenge - if you've got experience or a PoV, drop me a line.