Common PFAS Chemicals
Chemistry of Common PFAS Chemicals
The term PFAS (per- and polyfluoroalkyl substances) refers to a vast and diverse family of man-made chemicals that share a defining characteristic: carbon atoms where most or all of the carbon bonding sites are strongly attached to fluorine atoms. It’s this unique carbon-fluorine bond that gives PFAS their exceptional stability and resistance to heat, water, and oil. Within this extensive family, PFAS compounds can be categorised into two main groups: polymers and non-polymers.
PFAS Polymers
One significant class of PFAS compounds are fluoropolymers. These are large, complex molecules formed by linking many smaller PFAS units together into long chains. Common examples include:
- PTFE/Teflon® (Polytetrafluoroethylene): PTFE is famous for its non-stick properties, making it suitable for cookware, but also crucial in industrial applications for its low friction and chemical resistance.
- FEP (Fluorinated Ethylene Propylene): Known for its flexibility, clarity, and resistance to chemicals and UV radiation, often used in wiring, tubing, and non-stick coatings.
- ETFE (Ethylene Tetrafluoroethylene): A strong, durable material often used in architectural applications and as a protective coating.
- PFA (Perfluoroalkoxy Alkane): Used in linings, tubing, and high-performance applications.
These fluoropolymers share a few key properties:
- High molecular weight – their large size means they are not easily absorbed by living organisms
- Extreme stability – once formed into a seal, they are highly stable, insoluble in water and do not break down
PFAS Non-polymers
Non-polymers are smaller, more mobile, bioaccumulate (build up in the bodies of living organisms over time) and are more readily absorbed:
- Perfluoroalkyl Carboxylic Acids (PFCAs)
- Perfluoroalkyl Sulfonic Acids (PFSAs)
- Perfluoroalkyl Ether Carboxylic Acids/Sulfonic Acids (often called “Ether-PFAS” or “GenX chemicals”)
- Fluorotelomer Alcohols (FTOHs)
These non-polymer PFAS are the ones primarily responsible for the concerns about environmental persistence, bioaccumulation, and direct health effects that are driving much of the current regulatory action and research.
E&OE. This information was gathered by our manufacturing partners. For more information, visit www.dwi.gov.uk.