LAS BASES DE LOS FLUOROPOLIMEROS (EN INGLES)

Fluoropolymer Based Coatings

Teflon coatings consist of fluoropolymers, also known as fluorine polymers, which are responsible for many of Teflon’s unusual properties. Because of the coating’s resistance to solvents, acids and bases, and its friction-reducing effect, it’s a popular choice in both industrial and household applications. These unusual properties are a result of fluorine atoms, which benefit the polymers they comprise.

Fluorine atoms are relatively small with low polarizability but high electronegativity. When fluorine bonds with carbon, the bond is not only extremely strong but also leads to a thermally stable polymer. Perfluoropolymers, a class of fluoropolymers that consist entirely of carbon and fluorine bonds, offer several distinct advantages, such as chemical and weather resistance, oil and water resistance, low friction, and minimal surface adhesion. Depending on the particular strength of the carbon fluoride bond, other traits, such as resistance to soil, the ability to create a gas barrier, and insulation properties may be present in a fluoropolymer.

However, commonly used fluoropolymers in commercial use are not usually perfluoromers, but rather tetrafluoroethylene, vinylidene fluoride, or chlorotrifluoroethylene. These three forms of fluorine combine with other compounds to lend a coating increased chemical and flame resistance, thermal stability, and lubricity. Because of these favorable properties, such types of fluoropolymers are often effective for non-stick applications, such as cooking pots and pans, as well as in certain external coatings found on houses and large structural components that are frequently exposed to the elements. PTFE (polytetrafluoroethylene) and PVDF (polyvinylidenefluoride) are two common fluoropolymers, frequently used for these applications. However, because these coatings must be manufactured using high temperature processing which results in high crystallinity, they aren’t effective when used in conjunction with organic solvents.

Other classes of fluoropolymers may offer different advantages for certain applications. Such classes include, fluoroacrylates, fluorosilicone acrylates, fluorethanes, and perfluoropolyethers and perfluoropolyoxetanes.

• Fluoroacrylates
  This class of fluoropolymers is often found in easy-to-clean coatings and graffiti resistant coatings. Additionally, fluoroacrylates are used to treat certain paper and leather products, and can also serve as electronic application coatings. 

• Fluorosilicone Acrylates The addition of silicone to fluoropolymers enhances a coating’s slip resistance, hydrophobicity, and leveling. Polysiloxanes, when paired with fluorine, are easy coatings to make. Because of the addition of silicon, they tend to be more flexible than other fluoropolymers and retain their flexibility at temperatures ranging as low as -60 degrees C. 

• Fluoroethanes
  Because of fluoroethanes’ tendency to be either hydrophobic or extremely hydrophobic and therefore reduce erosion caused by rain, fluoroethane coatings are found in many aircraft, marine, and microwave communications systems. Urethane lends the coating its toughness, where as fluorine contributes low-surface energy. Certain coatings, depending on the manufacturing process, can be non-flammable as well as highly corrosion resistant.

• Perfluoropolyethers and Perfluoropolyextanes
  Perfluoropolyether (PFPE) is commonly used as a surfactant and is available in a variety of forms for a range of applications, and have the added benefit of not creating foam, as frequently occurs with other fluorine based surfactants. They are also non-toxic, exhibit chemical resistance, and can operate in an usually large temperature range, from -80 degrees to around 300 degrees C. Other characteristics include water resistance and repellence, improved flow, wetting, and leveling, and a high level of durability. Additionally PTFE based coatings are compatible with a variety of substrates and therefore widely used in numerous applications. Such applications include lending key characteristics to epoxy and polyurethane coatings, as well as comprising part of the chemical makeup of various inks and acrylics. Often, PFPE’s composition can be manipulated to create a coating that is also stain resistant.