Why Use Fluorosilicone Rubber?

13 Jan 2021 | Posted by Andrew Onions

Fluorosilicone rubber, which is often abbreviated to FVMQ or MFQ, differs from Silicone (VMQ) rubber in that some of the methyl groups are replaced by fluoroalkyl groups, consequently Fluorosilicone usually contains 23 to 28 percent fluorine.

FVMQ has almost the same mechanical and physical properties as conventional Silicone rubber and its low-temperature flexibility is just as good. In addition, because of its fluorine content it has better resistance to many liquids such as oils and fuels, essentially combining the inherently good resistance to swelling of Fluorocarbon Rubber (FPM) with the low temperature flexibility of VMQ. However, the operating temperature range is slightly reduced: -50 to +250°C for Fluorosilicone rubber when compared with -100 to +280°C on standard VMQ’s, or up to 300°C for special grades of VMQ.

The two materials also differ significantly in electrical insulating capability, which is very good in the case of silicone rubber but can only be brought up to a similar level in Fluorosilicone by means of modifying the formulation.

Characteristics of Fluorosilicone Rubber

Useful characteristics of Fluorosilicone:

• Excellent resistance to many automotive and aviation oils and fuels, chemicals, and solvents

• Extreme high- and low-temperature resistance

• Good low-temperature flexibility

• Good dielectric properties

• Excellent mechanical properties

• Good weathering resistance

• High ozone resistance

• Good ageing resistance

• Good rebound resilience

• Good water resistance

• Good bacterial Resistance

Not so useful characteristics of Fluorosilicone:

• High gas permeability

• Low tensile strength

• Poor abrasion resistance

• Low tear strength

Common Uses of Fluorosilicone Rubber

Whilst Fluorosilicone materials have been used in the automotive and aerospace industries for some time, they are gaining an increasing acceptance in the medical and pharmaceutical sectors where FVMQ’s inherent resistance to bacterial growth, suitability for contact with the body and ease of sterilization make it ideal for many applications including:

• Medical tubing
• Exhaust gas diaphragm
• Automotive seals and Engine gaskets
• Air pump valves
• Electrical connector inserts
• Turbocharger hoses
• O Rings
• Fuel line seals
• Leak detection seals and diaphragms

·        For more information on our high performance Fluorosilicone Rubber and Sponge, Fluorocarbon Rubber, and Silicone Rubber and Sponge materials and their applications please contact your account manager or phone our sales team.