fluorosilicone

Fluorosilicone refers to a class of silicone elastomers in which fluorinated organic groups are incorporated into the siloxane backbone, most commonly as trifluoropropyl side chains. The resulting materials, often marketed as fluorosilicone elastomers or fluorinated silicones (FVMQ), combine the flexibility and temperature stability of silicones with enhanced chemical resistance to fuels, oils, solvents, and some aromatics. They are typically supplied as two‑component addition-cure systems based on vinyl‑functional fluorinated siloxanes and hydrosilane crosslinkers, or, less commonly, peroxide-cured formulations.

Properties of fluorosilicone elastomers include superior resistance to automotive fuels and many solvents compared with conventional silicone rubbers, along with reduced swelling and improved long‑term stability in hydrocarbon environments. They also maintain good high‑temperature stability and ozone/oxidation resistance. However, these materials generally exhibit poorer low‑temperature flexibility, somewhat higher compression set at elevated temperatures, and higher density. They tend to be more expensive and less readily available than standard siloxane elastomers, and their processing can require specialized cure systems and handling due to the fluorinated monomers.

Applications of fluorosilicone elastomers are primarily in seals, gaskets, and diaphragms for automotive, aerospace, and chemical‑processing equipment, especially in fuel systems, fuel cells, and other environments where hydrocarbon resistance is critical. They are chosen when exposure to fuels and certain solvents would degrade other elastomers.

Limitations and considerations include higher cost, narrower processing windows, and the need for grade‑specific validation against target fluids and temperature ranges to ensure performance.