Fluorosilicone rubber and silicone rubber share many similar mechanical properties, particularly their flexibility over a broad temperature range and excellent resistance to environmental factors such as UV light, ozone, and aging. Each is regarded as a long-lasting elastomer that resists compression set across temperature extremes. Both materials maintain their elasticity at temperatures ranging from approximately -76°F (-60°C) to +392°F (+200°C), making them suitable for extreme-temperature applications. They are also widely used in applications in industries like automotive or aerospace and are noted for their durability and ability to form reliable seals.
Nonetheless, despite the similarities, there are differences between the two materials when meeting certain application requirements. If you’re considering either of these materials for an application, here’s what you need to know and what sets them apart from each other:
Fluorosilicone Rubber: Properties and Common Industrial Applications
Fluorosilicone rubber is often referred to as FSR or, by its technical abbreviation, FVMQ (Fluorosilicone Vinyl Methyl Rubber). They are essentially the same material, with FVMQ being the technical abbreviation used to describe the polymer structure of fluorosilicone. Either-or, fluorosilicone rubber is a specialized type of silicone elastomer that combines the properties of silicone rubber, such as flexibility over a wide temperature range, with the chemical resistance of fluorocarbons. Thus, it is well known for its excellent chemical resistance to fuels, oils, and solvents. This makes the material ideal for use in harsh environments or extreme conditions where exposure to aggressive fluids is expected. Because it is particularly valued for its stability and sealing capabilities, it is widely used in aerospace, automotive, and industrial applications.
In aerospace, for example, fluorosilicone is used in fuel line seals and gaskets due to its ability to withstand jet fuels and hydraulic fluids. Similarly, the automotive industry favors parts like turbocharger hoses and fuel system components that require durability in contact with gasoline, oil, and other chemicals. Its unique properties also make it valuable in the chemical processing and industrial machinery industries for seals, gaskets, and diaphragms that come into contact with aggressive fluids or require resistance to wide temperature fluctuations. Other applications include pharmaceutical processing equipment and military systems, where durable chemical and temperature resistance is necessary.
Silicone Rubber: Properties and Common Industrial Applications
Silicone rubber is a versatile, synthetic elastomer made from silicon, oxygen, carbon, and hydrogen. Like fluorosilicone, it is known for its flexibility and durability, wide temperature range, and thermal stability. Silicone also exhibits excellent resistance to weathering, UV radiation, moisture, and some chemicals; it is biocompatible and has insulating and dampening properties. Industrial applications for silicone rubber are varied and extensive. The material can be found in various automotive, aerospace, electronics, medical, and consumer goods components.
In the automotive industry, it is used for seals, gaskets, hoses, and spark plug boots because of its ability to withstand extreme temperatures and resist aging. In the aerospace industry, silicone rubber is employed in seals, O-rings, and gaskets for engines, airframes, and fuel systems, where its thermal stability ensures durability in high-altitude cold and engine heat. It’s also used in insulation materials for wiring, cabling, and vibration-dampening components. Similarly, silicone rubber is applied in keypads and protective coatings for electronics due to its excellent electrical insulation and dampening properties. The medical industry benefits from silicone’s biocompatibility and non-toxicity, making it suitable for medical tubing, seals, and implants. In consumer goods, cookware, and industrial machinery, silicone rubber components are used for applications requiring flexibility, durability, and resistance to environmental factors like moisture, UV light, and some chemicals.
Differences Between Fluorosilicone Rubber and Silicone Rubber
The key difference between the two elastomers lies in chemical resistance. Fluorosilicone rubber, adding fluorine groups to the main elastomeric polymer chain, offers superior resistance to fuels, oils, solvents, and other chemicals compared to standard silicone rubber. This makes fluorosilicone an ideal choice for applications where exposure to aggressive fluids is a concern, such as in aerospace fuel systems or automotive oil seals.
Although highly resistant to fuels, oils, and solvents, fluorosilicone has lower mechanical strength, including tear and abrasion resistance, compared to other elastomers like standard silicone or nitrile rubber. Another big difference between the two is cost. Fluorosilicone rubber is significantly more expensive due largely to its high production costs. Also, because there are not a lot of manufacturers of fluorosilicone rubber, there is limited material availability in many regions. This makes it less cost-effective for applications that do not require its unique chemical resistance and a drawback for large-scale production needs.
On the other hand, silicone rubber, while versatile, has disadvantages as well. Compared to other elastomers, it has relatively low tensile strength. This drawback makes the material unsuitable for components in high-stress or high-wear applications that require high tear resistance. It does not mesh well with certain chemicals, particularly hydrocarbons like gasoline and oils, making it unsuitable for prolonged chemical exposure applications. Though not as expensive as fluorosilicone, silicone is still more expensive than other elastomers due to the complexity of its production process.
In sum, fluorosilicone and silicone rubber offer many advantages for sealing applications. However, when comparing the overall differences between the two materials, while silicone is favored in applications where these mechanical properties and cost efficiency are more important, fluorosilicone is far more advantageous for applications in chemically harsh environments.
Contact the Experts at Manufacturer’s Rubber & Supply
If you’re considering one or the other, or if you’d like more information on fluoro silicone and silicone rubber applications and products or to discuss the best material to meet your sealing requirements, contact Manufacturer’s Rubber & Supply. We combine years of experience and expertise with an extensive inventory of industrial rubber products to meet all your sealing application needs.
