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The performance of fluoroelastomers in aggressive chemicals depends on the nature of the base polymer and the compounding ingredients used for moulding the final products (e.g. O-rings, shaft seals).
Studies indicate that types B and F (FKM- GBL-S and FKM-GF-S) are more resistant to acidic biodiesel. (This is because biodiesel fuel is unstable and oxidizing.) [citation needed] FKM O-rings have been used safely for some time in scuba diving by divers using gas blends referred to as nitrox. FKMs are used because they have a lower probability ...
In addition, chemical compatibility refers to the container material being acceptable to store the chemical or for a tool or object that comes in contact with a chemical to not degrade. For example, when stirring a chemical, the stirrer must be stable in the chemical that is being stirred. Many companies publish chemical resistance charts.
It is nonflammable [14] and the heat resistance is up to 175 °C. [15] It has a low coefficient of thermal expansion. The glass transition temperature (T g) is around 45 °C. [1] PCTFE has one of the highest limiting oxygen index (LOI). [16] It has good chemical resistance. It also exhibits properties like zero moisture absorption and non ...
FFKMs (by ASTM 1418 standard) (equivalent to FFPMs by ISO/DIN 1629 standard) are perfluoroelastomeric compounds containing an even higher amount of fluorine than FKM fluoroelastomers. They have improved resistance to high temperatures [ 1 ] [ 2 ] and chemicals and even withstand environments where Oxygen-Plasma are present for many hours.
The chemical resistance of a material or surface can be determined in compliance with ISO 2812 Paints and varnishes – Determination of resistance to liquids – Part 1: Immersion in liquids other than water (ISO 2812-1:2007 [1]); German Version EN ISO 2812-1:2007 or Part 4: Spotting methods (ISO 2812-4:2007 [2]); German Version EN ISO 2812-4:2007.
This contributes to their non-stick and friction reducing properties. Also, they are stable due to the stability multiple carbon–fluorine bonds add to a chemical compound. Fluoropolymers may be mechanically characterized as thermosets or thermoplastics. Fluoropolymers can be homopolymers or Copolymer. [citation needed]
Extruded fluoropolymer tubes such as FKM (Viton, Fluorel, etc.) have good compatibility with acids, hydrocarbons, and petroleum fuels, but have insufficient fatigue resistance to achieve an effective tube life. There are a couple of newer tubing developments that offer broad chemical compatibility using lined tubing and fluoroelastomers.