The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers. Integr Environ Assess Manag 2011;7:513–541. © 2011 SETAC

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Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins

More than 3000 per- and polyfluoroalkyl substances (PFASs) are, or have been, on the global market, yet most research and regulation continues to focus on a limited selection of rather well-known long-chain PFASs, particularly perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and their precursors. Continuing to overlook the vast majority of other PFASs is a major concern for society. We provide recommendations for how to proceed with research and cooperation to tackle the vast number of PFASs on the market and in the environment.

A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)?

Adsorption behavior and mechanism of perfluorinated compounds on various adsorbents--a review.

The present invention provides a fluoropolymer dispersion comprising fluoropolymer particles having an average particle size of 10 to 400 nm dispersed in water whereby the dispersion is free of fluorinated surfactant having a molecular weight of less than 1000 g/mol or contains the fluorinated surfactant having a molecular weight of less than 1000 g/mol in an amount of not more than 0.025% by weight based on the total weight of solids in the dispersion. The dispersion further comprises a non-ionic surfactant and an anionic surfactant selected from fluorinated anionic surfactants having a molecular weight of at least 1000 g/mol, non-fluorinated anionic surfactants and mixtures thereof.

Fluoropolymer dispersion containing no or little low molecular weight fluorinated surfactant

A method of making a fluoropolymer dispersion by first providing a fluoropolymer dispersion comprising fluoropolymer particles and one or more fluorinated surfactants selected from fluorinated carboxylic acids or salts thereof having the general formula:
 
[R f —O-L-COO − ] i X i+   (I)
 wherein L represents a linear partially or fully fluorinated alkylene group or an aliphatic hydrocarbon group, R f represents a linear partially or fully fluorinated aliphatic group or a linear partially or fully fluorinated aliphatic group interrupted with one or more oxygen atoms, X i+ represents a cation having the valence i and i is 1, 2 or 3; then adding one or more non-fluorinated surfactants selected from anionic and non-ionic surfactants followed by reducing the total amount of the one or more fluorinated surfactants to an amount of not more than 500 ppm, for example not more than 250 ppm based on the total weight of the dispersion while maintaining or increasing the amount of solids in the dispersion.

Method of making fluoropolymer dispersion

The present invention describes a novel process for the preparation of perfluorovinyl ethers. The process involves providing a hydrocarbon precursor that may be partially halogenated, fluorinating the precursor to provide a perfluorinated intermediate, and converting the perfluorinated intermediate to the desired perfluorinated ether. Novel perfluorovinyl ethers are also provided.

Fluorine containing vinyl ethers

Emulsifier free fluoropolymer manufacturing method in which (a) a chain transfer agent, or a mixture of chain transfer agents are used wherein the chain transfer agents do not yield more than 0.4 weight % relative to the monomer feed of water soluble fluorinated compounds, or (b) a chain transfer agent or a mixture of chain transfer agents selected from alkanes, dialkyl ethers, hydrofluoroethers and/or hydrofluorocarbons.

Emulsifier free aqueous emulsion polymerization process for making fluoropolymers

The invention provides a fluorinated surfactant having formula [Rf-(O)t-CHF-(CF2)n-COO-]i Xi+, wherein Rf represents a partially or fully fluorinated aliphatic group optionally interrupted with one or more oxygen atoms, t is 0 or 1 and n is 0 or 1, Xi+ represents a cation having a valence i and i is 1, 2 or 3. The surfactant can be used in emulsion polymerization of fluoromonomers to prepare fluoropolymers.

Fluorinated surfactants for making fluoropolymers

The present invention provides a process of reducing the amount of fluorinated emulsifier in an aqueous fluoropolymer dispersion by contacting the aqueous fluoropolymer dispersion with an anion exchange resin in a non fixed resin bed, the process comprising: (a) mixing the aqueous fluoropolymer dispersion with an effective amount of a surfactant so as to stabilize the fluoropolymer dispersion while being contacted with the anion exchange resin; (b) contacting the aqueous fluoropolymer dispersion with an anion exchange resin by agitating the aqueous fluoropolymer dispersion with an effective amount of anion exchange resin to reduce the amount of fluorinated emulsifier in the aqueous fluoropolymer dispersion to a desired level; and (c) separating the anion exchange resin from the aqueous fluoropolymer dispersion.

Werner Schwertfeger

Papers

Method of making fluoropolymer dispersion

Fluorine containing vinyl ethers

Emulsifier free aqueous emulsion polymerization process for making fluoropolymers

Fluorinated surfactants for making fluoropolymers

Process for reducing the amount of fluorinated surfactant in aqueous fluoropolymer dispersions