Coatings, fluoropolymer

Organic fluoropolymers have been used in many fields because they have special properties that no other polymers can provide. 

Coating is one of the important uses of fluoropolymers, since it enables them to exhibit their characteristics on the surface of a substrate. Some of the conventional fluoropolymers such as polytetrafluoroethylene [9002-84-0] (PTFE), tetrafluo-roethylene-hexafluoropropylene copolymer [25067-11-2] (FEP), and ethylene-tetrafiuoroethylene copolymer [25038-71-5] (ETFE) have been used as antistick or anticorrosive coatings. Only poly(vinylidene fluoride) [9002-58-1] (PVDF) has so far been used in paints. The major difficulties in employing thermoplastic fluoropolymers in paints and coatings result from their poor solubility in organic solvents and 

Coatings with Thermoplastic Fluoropolymers. Poly(vinylidene fluoride), PVDF, is the only conventional thermoplastic fluoropolymer that is used as a commercial product for weather-resistant paints. This crystalline polymer is composed of -CHjCFj- repeating units it is soluble in highly polar solvents such as dimethyl-formamide or dimethylacetamide. Poly(vinylidene fluoride) is usually blended with 20 30 wt% of an acrylic resin such as poly(methyl methacrylate) to improve melt flow behavior at the baking temperature and substrate adhesion. The blended polymer is dispersed in a latent solvent (e.g., isophorone, propylene carbonate, dimethyl phthalate). The dispersion is applied to a substrate and baked at ca. 300 °C for ca. 40-70 s. The weather resistance of the paints exceeds 20 years [2.16]-[2.18]. 

Commercial products include Kynar (Elf Atochem), Hylar (Ausimont), and Soles (Solvay). 

Copolymers of vinylidene fluoride with tetrafluoroethylene or hexafluoropropy-lene have recently been developed as an air-drying paint mainly for repair coating of the PVDF finish [2.19]-[2.21], Poly(vinylidene fluoride) is now widely used for coil coating of galvanized iron and aluminum sheets, and as a maintenance-free coating for walls of skyscraper buildings and roofing of industrial constructions. 

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Non-Metallic Materials Numerous engineering thermoplastics have been commercialised including materials such as polyetherether ketone (PEEK) and polyether sulphate (PES) with much improved thermal/chemical resistance. The usage of FRP equipment has increased, and fluoropolymer lining technology/applications have come of age. Of particular interest is the development of stoved, fluoropolymer coating systems for process industry equipment. 

Figure 8 Separation of isomeric acids (maleic and fumaric acid) by controlled surface porosity anion exchange chromatography. Column Sulfonated fluoropolymer coated onto a 50-p glass bead. Average pore size about 1000 A. Flow rate 2.73 ml/min. Eluant 10 mM HN03. Temperature 60°C. Detection absorbance. (Reproduced from Kirkland, J. J., J. Chromatogr. Sci., 7,361,1969. By permission of Preston Publications, A Division of Preston Industries, Inc.)...

For many applications it is desirable to be able to adjust the wetting properties of a solid surface for aqueous solutions. One method is called electrowetting [303,304], In electrowetting an electric potential is applied between a metal surface and a liquid via an electrode (Fig. 7.24). The metal is coated with an insulating layer of thickness h. Fluoropolymer coatings turned out to be suitable materials though it is not fully understood why [305], The change in contact... 

Scheirs, J., Fluoropolymer coatings new developments, in Polymeric Materials Encyclopedia (Salamone, J., Ed.), CRC Press, Boca Raton, FL, pp. 2498-2507 (1996). 

Fig. 3. Interfacial slip of an entangled melt at a non-adsorbing perfectly smooth surface, where the dots represent an organic surface (e.g., obtained by a fluoropolymer coating), which invites little chain adsorption. Lack of polymer adsorption produces an enormous shear rate jiat the entanglement-free interface between the dots and the first layer of (thick) chains. y-x=vs/a is much greater than the shear rate y present in the entangled bulk. This yields an extrapolation length b, which is too large in comparison to the chain dimensions to be depicted here...

Omniflex plus Solid fluoropolymer coating Compatibility Total HP... 

Corrosion resistant fluoropolymer coatings are currently marketed by W. L. Gore Associates, Inc. (Fluoroshield) and Pfaudler. 

Yamabe, M. 1994. Fluoropolymer coatings pp. 397-402. In Organofluorine Chemistry Principles and Commercial Applications (Eds. R.E. Banks, B.E. Smart, and J.C. Tat-low). Plenum Press, London. 

There are two distinct ways of coating a metal surface with a fluoropolymer coating. 

Some parts might need to have a coating thickness less than what other lining processes can provide. These might include valves, tubes, pipes, and impellers. These parts may still need to be protected by a fluoropolymer coating. One of the best references is published by the Powder Coating Institute although other sources are also available. 

R. A. lezzi, Fluoropolymer coatings for architectural applications in Modem Fluo-ropolymers(Ed. J. Schreir), John Wiley ... 

Chem. Descrip. Nonstick fluoropolymer coatings Uses Nonstick coatings for frying pans, bakeware, etc. 

Hexafluoropropylene/vinylidene fluoride/ tetrafluoroethylene teipolymer, Viton A-100 Viton A-200 fluoroelastomer, tank coatings Hexafluoropropylene/vinylidene fluoride/ tetrafluoroethylene terpolymer fluoroelastomer, tank solution coatings Viton A-100 Viton A-200 fluoroelastomer, thin film Fluordatex 200 fluoropolymer modifier Dynasylan F 8815 fluoropolymer, coatings Dyneon THV 220A Teflon PTFE 30 Teflon TE-3667N... 

Fluoropolymer-coated glass fabric is a new system with adjustable translucency up to 50% and a high tensile strength. 

In special cases that have some other requirements, fluoropolymer-coated or silicone-coated fibreglass fabrics are increasingly being used. These materials are preferred mainly for foils and coatings and topcoats of fabrics, due to their thermal and chemical stability as well as their good... 

After batching, the powder was attrition milled (Model HD-01 Union Process, Akron, OH) in hexane at 600 rpm for 240 min in a fluoropolymer coated bucket using tungsten carbide media and a tungsten carbide spindle to reduce the starting particle sizes. The powder was again dried by rotary evaporation. 

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