Fluoroelastomer

Fluoroelastomer is a class of synthetic elastomers with very high fluorine content, also known as fluorinated elastomers or FKM. The most common members are fluorinated copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), often with a third fluorinated monomer such as a fluorinated ether (for example PMVE or TFVE) to tailor properties. These polymers are typically produced as copolymers or terpolymers and cured to form elastic rubbers. They are used in various grades and formulations to balance chemical resistance, temperature performance, and mechanical properties.

The key feature of fluoroelastomers is their exceptional resistance to oils, fuels, solvents, and ozone, along with high temperature stability. Many formulations remain elastomeric up to about 200–250°C (depending on the cure system and co-monomers) and exhibit low gas and liquid permeability. They also retain properties over a wide pH range and resist weathering. However, they often show limited low-temperature flexibility, may exhibit higher compression set after prolonged heating, and can be susceptible to swelling in some polar solvents, especially certain ketones and esters. Processing typically requires specialized cure systems, such as peroxide-based vulcanization, and fluorinated curing chemistries, which can increase material cost and complicate processing compared with non-fluorinated elastomers.

Common applications include seals and gaskets in automotive engines and fuel systems, aerospace components, chemical processing equipment, pumps, and valves. Fluoroelastomers are chosen when resistance to fuels, oils, solvents, and high-temperature exposure is essential, and they are widely specified in harsh or chemically aggressive environments.