Fluorocarbon elastomers are highly fluorinated, carbon based polymers, which resist to chemical attacks and ozone. The service temperature lies between –20°C and 204°C, temporary there is also a higher service temperature possible. In contrast to the FFKM’s, in the FKM’s there are hydrogen atoms present within the polymer chain. Depending on their different properties the FKM’s can be classified in more subgroups:
- low temperature elastomers
- baseresistant elastomers
Common fluoroelastomer-copolymers consist of vinylidenefluoride (VDF) and hexafluoropropylene (HFP), they typically contain a fluorine fraction of 65-66mass% and they are the most used polymers within the fluorocarbon elastomers. The fluorocarbon elastomer terpolymers contain, in addition to VDF and HFP, also tetrafluoroethylene (TFE) as third component. The increase of the fluorine fraction in the fluorocarbon elastomer causes a improved chemical and thermal resistance. The typically fluorine fraction in this kind of fluorocarbon elastomers amounts to 67-70mass%. By variation of the different components in the fluorocarbon elastomer terpolymers the fluorine fraction can be adjusted, the increase of the fluorine fraction in the terpolymer leads to an increase of the flow-resistance.