Technical Library


Many advantages of fluorocarbons and silicones are combined in fluorosilicones. The materials are useful from -40 to 230 °C in a wide range of aggressive service environments. They have achieved a number of unique applications due to their chemical- and solvent-resistance to lubricity. Fluorosilicones are not miscible with fuels or oils and have a solubility parameter of 9.6. They have been employed in mechanical vacuum pumps where exposure to high temperature moisture and oxygen is encountered.

The fluids are excellent lubricants under extreme pressure applications. This characteristic, considered with resistance to fuels, has led to many automotive and aerospace lubrication applications, since they are not easily leached by fuels from mechanical joints. In addition, fluorosilicones, particularly the copolymers, have been employed as lubricants for electrical contacts and precision timing devices. Greases formulated from fluorosilicones and solid fluoropolymer thickeners have been used in sealed transmission and other extreme pressure applications.

The high density of these fluids has led to their use as a flotation medium for inertial guidance systems. Acoustic velocities in fluorosilicones are lower than conventional silicones, allowing sonar lens development. Trifluoropropylmethylsiloxane homopolymers have a compressibility of 7.5% at 20,000 psi. Volume resistivity for fluids > 500 cSt: 1,013 ohms-cm.

Fluorosilicone Fluids

Poly(3,3,3-trifluoropropylmethylsiloxane), CAS: [63148-56-1]

Product codeViscosity (cSt)Viscosity temperature coefficientPour point (°C)Transition temperature (Tg °C)DensityRefractive indexSurface tensionDielectric constantDielectric strengthFlashpoint (°C)Molecular weight

Specialty Fluorosilicones

Product codeDescriptionViscosity (cSt)Viscosity temperature coefficientPour point (°C)Transition temperature (Tg °C)DensityRefractive indexSurface tensionDielectric constantDielectric strengthFlashpoint (°C)Molecular weightCAS
FMS-221(48-52% 3,3,3-trifluoropropylmethylsiloxane)-(48-52% dimethylsiloxane) copolymer 80-120---55-1031.161.38721.4------1,800[115361-68-7]
FMS-222R*(48-52% 3,3,3-trifluoropropylmethylsiloxane)-(48-52% dimethylsiloxane) copolymer 140-200---55-1031.171.38821.4------2,000[115361-68-7]
FMS-411(25-35%-nonafluorohexylmethylsiloxane)-(65-75% dimethylsiloxane) copolymer 8-12---40--1.221.365--------1,000[882878-48-0]
FMS-736(15-20%-tridecafluorooctylmethylsiloxane)-(80-85% dimethylsiloxane) copolymer 4,000-7,000------1.211.37521.1----31540,000[115340-95-9]
SIB1816.01,3-bis(tridecafluorooctyl)tetramethyldisiloxane 6-7------1.461.337--------826[71363-70-7]
R&D only
*reduced volatility grade (< 2% volatiles measured after 4 hours at 150 °C)

Fluorocarbon-Fluorosilicone Light Grease

Product codePenetration 60 strokeDropping-point (°C)4-ball wear (mm, 232 °C)
*1,200 rpm, 40 kg, 2 hrs, M-10 steel