Fluorosilicones

Fluorosilicones are a family of silicone-based polymers and elastomers in which fluorinated groups are attached to the silicon-containing backbone. The term covers fluorosilicone elastomers (often classified as FVMQ), as well as fluorinated silicone fluids, oils, and resins. In these materials, the siloxane chain (-Si-O-Si-) carries substituents such as trifluoropropyl or other fluorinated alkyl groups, which impart higher polarity and chemical resistance than ordinary silicones.

The fluorinated substituents give fluorosilicones exceptional resistance to fuels, lubricants, solvents, and many chemical environments, along with good thermal stability and weathering. They typically retain flexibility over a wide temperature range, including low temperatures, but their overall high-temperature performance and compression set can be inferior to conventional silicone elastomers and much inferior to fluorinated elastomers (FKMs). They tend to be more expensive and can exhibit limited mechanical strength relative to some alternatives.

Fluorosilicones are used where silicone performance must be balanced with chemical resistance to fuels and solvents, such as seals, gaskets, O-rings, and hoses in automotive, aerospace, and chemical-processing equipment. Fluorosilicone fluids and resins are used in specialty lubricants, coatings, and dielectric fluids, particularly where immiscibility with water and compatibility with high-temperature fuels are desired.

Manufacture and curing: Fluorosilicone polymers are prepared by incorporating fluorinated silane or siloxane monomers and may be cured by standard silicone chemistries, including platinum-catalyzed hydrosilylation for elastomers. Market grades include FVMQ elastomers suitable for automotive fuel systems, aerospace components, and chemical processing lines.