in this article, Amir illustrates the technical background related to fluorinated surfactants production, applications, and recent legal dispute in the united states, with focus on the image problem in the chemical industry
The term perfluoro-alkyl substances (PFAS) is generally used to refer to fluorinated surfactants which have been commercially available for more than 70 years till now. The first available were perfluorinated sulfonic acids such as perfluoro-octanesulfonic acid (PFOS). The most common commercially produced are perfluorinated carboxylic acids such as perfluoro-octanoic acid (PFOA).
The fact that fluorine atoms are present in surfactant molecules modifies behaviour compared to classical surfactants by lowering surface tension in aqueous blends which makes fluorinated surfactants effecient stain removers that penetrate into pores and soiled areas.
Furthermore the fluorine atoms provide an outstanding chemical and thermal stability which makes flourinated surfactants the main ingredient in fire fighting foams, the convenient impregnation agent for textiles in apparel industry, mist supressant in metal plating, also as an emulsifier in polymerization of polytetrafluoroethylene (PTFE), fluorinated synthetic rubber, and membranes which are used in chloro-alkali electrolyzers.
Fluorinated Surfactants : Forever Chemicals
The widespread use and disposal of perfluoro-octanesulfonic acid (PFOS), Perfluoro-octanoic acid (PFOA), and their salt derivatives -due to the high stability- has resulted in widespread presence in the environment. In addition, they are possible carcinogens, liver toxicants, immune system toxicants, and were listed as "substances of very high concern" by European Chemicals Agency (ECHA).
This caused commercial production to shift toward short chain alternatives such as perfluorinated ethers due to the deteriorating reputation within the technical community that usually refer to these chemicals as "forever chemicals". thus both perfluoro-octanesulfonic acid (PFOS) and Perfluoro-octanoic acid (PFOA) have been phased out of production in the United States in 2002 and 2015 respectively.
Perfluoro-octanoic acid (PFOA) was the subject of the movie "dark waters" based on the legal dispute in polluted areas in west virgina that pushed forward the phasing out.
However, there remains a need for perfluorinated carboxylic acids to obtain the beneficial performance properties that cannot be achieved with perfluorinated ether alternatives. For this reason hybrid class of fluorinated surfactants which combines characteristics of perfluorinated carboxylic acids and perfluorinated ether is being produced in the United States by Chemours, which spun-off DuPont in 2015. The hybrid class is known as perfluoro-propoxylated carboxylic acids such as hexafluoropropylene oxide dimer acid (HFPO-DA) and its ammonium salt derivative GenX .
Fluorinated Surfactants : Production
Here you will find brief descriptions, industrial synthetic routes, and simplified flow diagrams to further illustrate the production process for perfluoro-octanesulfonic acid (PFOS), perfluoro-octanoic acid (PFOA), and hexafluoropropylene oxide dimer acid (HDPO-DA).
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GenX : Image Problem
The chemical clash started when European Chemicals Agency (ECHA) listed Gen:X as "substance of very high concern" followed by media hype that is taking advantage by linking the new hybrid class to the phased out PFOA.
No-matter-when a chemical product reputation is being taken down by media that means new competitors are emerging to the market, because there is no methodical approach for chemical toxicity classification
It is obvious that there is no powerful lobby for fluorinated surfactants. That explains why Chemours spun-off DuPont in the same year PFOA was phased out. Chemiprobe started “probing” on this case study since september, and continuously networking with Professionals in the fluorinated surfactants trade. In Conclusion, The media hype is influenced by pressure group that is lobbying for fluorinated protein-based foams -biodegradable alternatives- produced by companies in Germany, France, Finland, and Netherlands. That explains why it was European Chemicals Agency which listed Gen:X as "substance of very high concern".
Insights Timeline
apparel brands including patagonia, ralph lauren, american eagle, levi, and brands of PVH corporation have announced commitments to generally phase out PFAS across product lines to further pressure Chemours for product elimination upon net income decline on higher raw material and public image deterioration >> Feb 11 , 2022
new report released by non-governmental organizations including NCPIRG Education Fund , Natural Resources Defense Council (NRDC) , and Fashion FWD have ranked apparel brands on commitments to phase out PFAS across product lines to pressure brands like walmart, costco, tapestry, and G-III apparel Group >> Apr 7 , 2022
classical surfactants : linear alkyl benzene sulfonic acids (LABSA) such as laurylbenzene sulfonic acid that is found in laundry powder, dishwashing liquid, and personal care products
foam blanket mechanism : separating the fuel from the air it needs to burn. Therefore, fluorinated surfacts are foaming agents, and water content of the foam provides cooling effect
textile impregnation : treating fabrics with chemicals to obtain special properties such as high thermal stability and fire-resistance
mist suppressants : surfactants that reduce the surface tension of the electrolyte solution, which reduces the size and energy of the gas bubbles generated in metal plating electrolysis
perfluorinated sulfonic and carboxylic acids : do not breakdown in the environment through chemical or biological degradation