One of the materials you can choose from for rubber seals is FFKM. This material has been specially developed for use in extreme conditions, such as in oil refineries, the chemical process industry and aerospace industry. In this article we explain if, and when, FFKM O rings can be applicable for your situation.
What is FFKM?
FFKM consists of 3 monomers: tetrafluoroethylene (TFE), perfluoromethyl vinyl ether (PMVE) and cure site monomer (CSM). PTFE, also known as Teflon, is a thermoplastic material and consists of TFE. In this material there are no hydrogen atoms in the chain which consists of C-F compounds. This makes the material to become chemically inert. In FFKM, the PMVE ensures the elastic behaviour and the CSM makes it possible to create cross-links that give the material its sealing properties.
As a result of this composition, perfluoroelastomer (or FFKM or FFPM) has a high chemical resistance and the material is resistant to more than 1800 different chemicals, such as concentrated nitric acid, sodium hydroxide, ethylene diamine and steam. In addition, the material offers high temperature stability (327°C). And it has excellent sealing properties. The material is therefore similar to PTFE, but has much better sealing properties.
What is FFKM used for?
Because of these properties FFKM seals can be used well in extreme conditions and regular replacement is not necessary. As a result, significant savings in maintenance costs can be achieved. FFKM seals are therefore mainly used in oil refineries, the chemical process industry, aviation, the semiconductor industry, the pharmaceutical industry and the vacuum industry.
By curing the material (applying the cross-links) the material acquires its elastic properties and becomes an elastomer.
Different curing systems are possible, each with their own specific properties:
What are the disadvantages of FFKM O rings?
FFKM is not suitable for every application. For example, it must be taken into account that the material does not work optimally at low temperatures.
What are the advantages of FFKM O rings?
The excellent chemical resistance also in combination with the high temperature range.
The permeability is low and the material has low outgassing values, especially at temperatures above 200°C. This makes it ideally suited for vacuum applications, especially in the Semicon industry. The sealing effect also remains very good over the entire temperature range for a long time, unlike silicone seals, for example.
Are you interested in this sealing rubber and would you like to know if FFKM is suitable for your application? Then please contact us using the contact form below.