Overview of the Development of the Fluoropolymer Industry (original) (raw)
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Integrated environmental assessment and management, 2018
Per- and poly-fluoroalkyl substances (PFAS) are a group of fluorinated substances that are in the focus of researchers and regulators due to widespread presence in the environment and biota, including humans, of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Fluoropolymers, high molecular weight polymers within the PFAS group, have unique properties that constitute a distinct class within the PFAS group. Fluoropolymers have thermal, chemical, photochemical, hydrolytic, oxidative and biological stability. They have negligible residual monomer and oligomer content and low to no leachables. Fluoropolymers are practically insoluble in water and not subject to long-range transport. With a molecular weight well over 100,000 Da, fluoropolymers cannot cross the cell membrane. Fluoropolymers are not bioavailable or bioaccumulative, as evidenced by toxicology studies on PTFE: acute and subchronic systemic toxicity, irritation, sensitization, local toxicity on implantation...
IOP Conference Series: Materials Science and Engineering
This work features the properties and the common industrial applications of two thermoplastic polymers which are the Polyvinyl fluoride (PVF) and the Polyvinylidene fluoride (PVDF), the polymerization and the manufacturing processes of their monomers have been emphasized in this work. It is believed that these two materials are having a number of shared properties and applications. Their distinguishing characteristics allow them to be utilized in various applications with immense interest to the industrial world. They excel, converge, and slightly diverge in most of their properties with diverse transition phases as well as piezoelectric and pyroelectric effects. Their eminent properties qualify them to be used in a number of industrial and outdoor applications e.g. insulations, sensing materials, laminations, encapsulations, coatings, membranes, biomaterials, aircraft interiors and photovoltaic applications. In conclusion, this work recommends further in-depth analysis to investigate the correlations between these two polymers and to provide oriented numerical information on their performance.
Polyvinyl fluoride (PVF); Its Properties, Applications, and Manufacturing Prospects
IOP Conference Series: Materials Science and Engineering
Polyvinyl fluoride (PVF) is a distinctive polymer with excessively studied properties. The wide utilization of this polymer has dramatically escalated due to its outstanding properties (e.g., mechanical strength, chemical resistance, high stability, low permeability, indoor functionality, outdoor durability, light transmissibility, adherence, stain resistance, sunlight degradation, and high temperature endurance). An overview of the chemical, physical, electrical, and thermal properties of PVF is provided. The current applications of PVF/Tedlar®, its polymerization, and the manufacturing processes are also addressed in this work. A comparative analysis has been conducted to explore common and uncommon properties of PVF, fluoropolymers, and competing polymers such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyvinyl chloride (PVC). Overall, PVF is anticipated to have further promising manufacturing prospects in numerous industries and in various fields suc...
Properties of thermally sprayed fluoropolymer PVDF, ECTFE, PFA and FEP coatings
Progress in Organic Coatings, 2004
Thermally sprayed fluoropolymer, polyvinylidene fluoride (PVDF), ethylene chlorotrifluoroethylene (ECTFE), perfluoroalkoxy alkane (PFA) and fluorinated perfluoroethylenepropylene (FEP) coatings were produced by flame and plasma spraying processes. It was possible to produce high quality coatings by these techniques. These coating processes are one-step methods in which post heat treatments are not required, in contrast to conventional electrostatic deposition methods. Morphology and particle size distributions were determined for each fluoropolymer powder. The coatings prepared by plasma and flame spraying were studied by optical microscope, salt spray test and liquid immersion tests. Sprayed coatings were found to be poreless and very smooth. In salt spray test, no corrosion invasion was found. In both liquid immersion tests (pH values −0.7 and 14) only PFA coating performed well. The other coatings showed a little corrosion in liquid immersion tests. That was observed as darkening of the fluoropolymer coating in the areas that were exposed to corrosive liquid. According to sectioned micrographs, the coatings were fully dense.
Low-temperature fluorination of fluoro-containing polymers
Journal of Fluorine Chemistry, 2006
The direct fluorination of polyvinylidenefluoride (PVDF) and the copolymer of tetrafluoroethylene with ethylene (CTE) was studied at 35-300 K. The dependence of radical formation on temperature and reaction time was obtained by use of electron paramagnetic resonance (EPR) spectroscopy. Primary alkyl radicals formed as a result of the reaction of fluorine abstracting a hydrogen from the polymer were detected at 35 K. These radicals rapidly react with molecular oxygen producing long-lived ($48 h at 300 K) peroxy radicals. The peroxy radicals when subjected to UV-irradiation (l < 280 nm) give rise to other radicals that are not stable at T > 77 K. The concentration of the radicals produced during fluorination of PVDF at 77-200 K is one order of magnitude less than that formed from CTE under similar conditions. A mechanism based on the abstraction of the H and the energies of the C-H bonds is given. Density functional theory was used to predict the structures and EPR parameters for a number of fluorinated radicals to explain the observed spectra. The FOO radical was detected at low temperatures.
The Depolymerization of Poly(tetrafluoroethylene) US Pat. 3,832,411
US Patent 3,832,411, 1974
Poly(tetrafluoroethylene) [9002-84-0] was thermally depolymerized to give mainly tetrafluoroethylene [116-14-3], by passing steam of 425-650.deg. at a .geq.4:1 steam-product(g) molar ratio over I. Thus, 250 g steam was generated within 30 min and passed over 100 g I [enclosed by a stainless steel sieve in a stainless steel tube (length 1070 mm, diam. 25 mm)] at 455.deg. and 60:1 steam-product molar ratio. I (21 g) was pyrolyzed to give a product(g) consisting of F2C:CF2 98, C3F6 1.25, and C4F8 0.75%.
Environmental Science & Technology, 2020
Fluoropolymers are a group of polymers within the class of per-and polyfluoroalkyl substances (PFAS). The objective of this analysis is to evaluate the evidence regarding the environmental and human health impacts of fluoropolymers throughout their life cycle(s). Production of some fluoropolymers is intimately linked to the use and emissions of legacy and novel PFAS as polymer processing aids. There are serious concerns regarding the toxicity and adverse effects of fluorinated processing aids on humans and the environment. A variety of other PFAS, including monomers and oligomers, are emitted during the production, processing, use, and end-of-life treatment of fluoropolymers. There are further concerns regarding the safe disposal of fluoropolymers and their associated products and articles at the end of their life cycle. While recycling and reuse of fluoropolymers is performed on some industrial waste, there are only limited options for their recycling from consumer articles. The evidence reviewed in this analysis does not find a scientific rationale for concluding that fluoropolymers are of low concern for environmental and human health. Given fluoropolymers' extreme persistence; emissions associated with their production, use, and disposal; and a high likelihood for human exposure to PFAS, their production and uses should be curtailed except in cases of essential uses.