Silicone and fluorosilicone rubbers are often confused, but they have key differences. Understanding these differences can help in choosing the right material for your application.
Silicone and fluorosilicone differ in chemical resistance, temperature stability, and suitability for specific industrial applications.
Understanding these differences is crucial for selecting the appropriate material for your needs.
What is Fluorosilicone?
Selecting the right rubber material is essential for product performance. Fluorosilicone offers unique properties worth considering.
Fluorosilicone is a hybrid material that blends silicone’s flexibility with fluorine’s resistance to fuels, oils, and harsh chemicals.
Composition and Properties
Fluorosilicone is created by incorporating fluorine into the silicone backbone, resulting in a material that offers exceptional resistance to various harsh chemicals, oils, and fuels. While silicone rubber is already known for its high-temperature resistance and flexibility, fluorosilicone takes these properties a step further by providing resistance to even more aggressive chemicals, including those found in automotive fuels and industrial solvents. This makes fluorosilicone ideal for applications in the aerospace, automotive, and chemical processing industries, where exposure to extreme conditions is common.
Is Fluorosilicone Oil Resistant?
Ensuring material compatibility with oils is vital in many industries. Fluorosilicone's performance in such environments is noteworthy.
Fluorosilicone is highly resistant to oils and fuels, making it suitable for automotive and aerospace applications.
Oil Resistance Comparison
| Property | Silicone Rubber | Fluorosilicone Rubber |
|---|---|---|
| Oil Resistance | Moderate | Excellent |
| Temperature Range | -50°C to 250°C | -60°C to 200°C |
| Flexibility | High | Good |
Fluorosilicone's resistance to oil is due to the fluorine atoms incorporated into the polymer. These fluorine atoms are highly electronegative and create strong bonds with carbon, making it difficult for oils and fuels to break down or degrade the material. As a result, fluorosilicone is often used in industries like automotive, aerospace, and chemical processing, where exposure to oils, lubricants, and fuels is common. In fuel systems, gaskets, seals, and O-rings made from fluorosilicone can maintain their integrity even when exposed to aggressive chemicals.
Is Fluorosilicone Conductive?
In applications where electrical insulation is critical, understanding a material's conductivity is essential.
Fluorosilicone is non-conductive, maintaining excellent electrical insulating properties similar to standard silicone.
Electrical Properties
Fluorosilicone, like standard silicone, is a non-conductive material, making it suitable for applications requiring electrical insulation. Its excellent resistance to high temperatures and chemical exposure further enhances its suitability for electrical components. Fluorosilicone is often used in environments where electronic components are exposed to extreme conditions, such as in automotive or aerospace applications. Seals and gaskets made from fluorosilicone prevent electrical short circuits while offering resistance to the harsh chemicals often found in these industries.
Is Fluorosilicone Flammable?
Safety considerations include a material's flammability, especially in high-temperature environments.
Fluorosilicone exhibits high flame resistance, making it suitable for applications exposed to high temperatures and potential fire hazards.
Flame Resistance
Fluorosilicone’s flame resistance comes from its chemical structure. The presence of fluorine atoms in the polymer chain imparts a high degree of stability to the material, even under extreme temperatures. Unlike many other elastomers, fluorosilicone does not easily catch fire, and it will not support combustion under typical exposure conditions. This property makes fluorosilicone an ideal material for sealing and gasketing in industries like aerospace, where components must operate in high-temperature environments without the risk of ignition or failure.
What is Fluorosilicone Used For?
Identifying the appropriate applications for fluorosilicone can guide material selection in various industries.
Fluorosilicone is commonly used in aerospace, automotive, and chemical processing industries due to its resistance to extreme conditions.
Common Applications
| Industry | Application | Fluorosilicone Benefits |
|---|---|---|
| Aerospace | Fuel system seals, O-rings | Resistance to fuels, oils |
| Automotive | Gaskets, fuel lines, seals | Durability in harsh environments |
| Chemical Processing | Seals for fluid systems | Resistance to chemicals, high temperatures |
Due to its remarkable chemical resistance, fluorosilicone is commonly used in industries that require materials capable of handling extreme environments. In the aerospace industry, fluorosilicone is used for sealing components in fuel systems and engine compartments, where exposure to jet fuels and oils is frequent. In automotive applications, it is used for gaskets, O-rings, and seals in fuel systems, which are often exposed to gasoline and other volatile compounds. The chemical stability of fluorosilicone also makes it a popular choice in chemical processing and industrial fluid handling systems, where the material must withstand exposure to corrosive chemicals and extreme temperatures.
Silicone and Fluorosilicone comparison
Silicone1 (VMQ) and fluorosilicone (FVMQ) are both synthetic elastomers used in various industries for their unique properties. Silicone is made from silicon, derived from quartz, and has excellent heat and ozone resistance, as well as high dielectric stability. Fluorosilicone2 is a type of silicone rubber that remains stable in high temperatures and can withstand harsh weather and ozone. The key difference between them lies in chemical resistance; fluorosilicone contains additional properties common to fluorocarbons.
Here's a comparison of silicone and fluorosilicone:
Material Properties:
- Temperature Resistance3:
- Silicone: -76°F to 437°F (Standard), -150°F to 572°F (Special)
- Fluorosilicone: -76°F to 350°F (Standard), -76°F to 450°F (Special)
- Hardness:
- Silicone: 20 to 80 Shore A
- Fluorosilicone: 40 to 80 Shore A
- Resistance:
- Silicone: Engine/transmission oil, diluted salt solutions, moderate temperature water, dry heat.
- Fluorosilicone: Fuels, aromatic mineral oils, benzene, toluene, chlorinated/aromatic hydrocarbons.
- Limitations:
- Both: Poor abrasion resistance, high friction, susceptible to ketones, unsuitable for dynamic sealing.
- Silicone: Concentrated acids/alkalis, petroleum oils/fuels, steam (>248°F).
- Fluorosilicone: Brake fluids, hydrazine.
- Cost: Fluorosilicone ~5x more expensive than silicone.
Applications:
- Silicone: Food, medical, semiconductor, automotive, aerospace, electronics, irrigation, military. Electrical seals, engine gaskets, turbine seals, hydraulic seals, medical pumps, ventilators, IV components, feeding devices.
- Fluorosilicone: Aerospace/automotive fuel systems, static sealing, petroleum oil applications, chlorinated solvent environments. Jet fuel systems, auto fuel emissions control.
Curing:
- Peroxide-cured (standard for both).
- Silicone: Platinum-cured (better flexibility, low volatile matter). Requires clean room, platinum catalyzer (more expensive).
| Feature | Silicone (VMQ) | Fluorosilicone (FVMQ) |
|---|---|---|
| Temperature Range | -76°F to 437°F (Special up to 572°F) | -76°F to 350°F (Special up to 450°F) |
| Hardness (Shore A) | 20-80 | 40-80 |
| Resistance | Heat, Ozone, Engine/Transmission Oil | Fuels, Oils, Solvents, Chlorinated Hydrocarbons |
| Limitations | Poor Abrasion, Acids/Alkalis, Steam | Poor Abrasion, Brake Fluids, Hydrazine |
| Typical Uses | Seals, Gaskets, Medical Devices | Fuel Systems, Harsh Chemical Environments |
| Cost | Lower | Significantly Higher |
| Curing | Peroxide, Platinum | Peroxide |
Conclusion
Both silicone and fluorosilicone offer unique advantages depending on the application. Silicone is widely used for its high flexibility and temperature resistance, while fluorosilicone is the better choice for applications requiring exceptional chemical resistance. When deciding between the two, consider the specific environmental conditions and performance requirements of your application.
Footnotes：
-
Discover the diverse applications of Silicone across industries, from medical to aerospace, and its benefits. ↩
-
Explore the unique advantages of Fluorosilicone for various industrial uses, especially in harsh environments. ↩
-
Learn how Temperature Resistance plays a crucial role in selecting materials for engineering applications, ensuring safety and performance. ↩
