What Are PFAS – Polymerized vs Non-Polymerized Forms

Per- and polyfluoroalkyl substances (PFAS) are a broad group of substances that contain carbon-fluorine bonds, which are the strongest chemical bonds in organic chemistry. Substances broadly defined as PFAS range from fluorine-based gases to textile coatings, firefighting foams, and fluoropolymers. However, not all PFAS are the same.

PFAS can be sub-grouped into two categories: polymers and non-polymers. This sub-grouping is helpful in more accurately understanding each group’s composition, physical behaviors, and, ultimately, their interactions with the environment. It is well-accepted that polymers generally have very different properties and behave very differently than non-polymers.

This difference in behavior between polymers and non-polymers is due to the size of the molecule. For instance, the difference in size between a typical small molecule PFAS (non-polymer) and a typical PTFE chain (polymer) is the difference between the length of an ant and the length of a blue whale. This massive size difference changes the physical state, mobility, solubility, bio-reactivity, and mechanical properties of the substance.

An example of a non-polymeric PFAS product used in industry is that of dispersive firefighting foams, in which small molecule non-polymeric PFAS serve as surfactants that spread the foam to suppress the fire. An example of a polymeric PFAS product used in industry would be solid fluoropolymer tubing. While both are broadly classified as PFAS products, it is important to recognize the difference between the polymerized form (solid tube), and the non-polymerized form (liquid mixture).

You can learn more about the safety and differences between polymerized and non-polymerized forms of PFAS here:

• A review of the differences in safety between fluoropolymers and non-polymerized forms of PFAS
• Not All PFAS are the Same

You can learn more about the proposed regulations against PFAS here.