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Fluorosilicone vs. Silicone: the Major Differences You Need to Know

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Every rubber compound has its own unique properties that make it the right choice for a specific application. When it comes to silicone, there are special variations that offer greater resistance or chemical compatibility properties.

Fluorosilicone is a variation of silicone rubber that maintains excellent high temperature stability and mechanical properties, while offering greater resistance to fuel, oil and other chemicals. These added benefits also come with a cost—fluorosilicone is typically five times the cost of silicone. While these two rubber materials share many similarities, there are important differences that set these two apart in terms of applications they are suited for. Here’s a closer look at the major differences between silicone and fluorosilicone. 

 

Breaking Down the Mechanical Differences

Silicone is developed from silicon, hydrogen and oxygen and is known for its flexibility at extreme temperatures and low compression set characteristics. The working mechanical properties of silicone include: 

  • Temperature resistance of standard compounds range from -85°F to 400°F
  • Hardness ranges from 20 to 80 Shore A
  • Stable in extreme temperature environments
  • Compatible with FDA regulations

Fluorosilicone shares the excellent temperature resistance and stability properties of silicone. However, the two rubbers differ in that fluorosilicone also offers additional benefits and slightly different mechanical properties that make it a desirable elastomer for certain industries. These properties include:

  • Temperature resistance of standard compounds range from -75°F to 400°F
  • Hardness ranges from 40 to 80 Shore A
  • Resistant to fuel, oil, solvent and water
  • Offers excellent resistance to weather and ozone

Both silicone and fluorosilicone are limited by their poor abrasion resistance and high friction characteristics. Because of these limitations, they are not recommended for dynamic sealing. Additionally, both rubbers are not recommended for exposure to ketones. To learn more about the mechanical properties of silicone and fluorosilicone, visit our Material Selection Guide

 

Recommended Applications for Silicone and Fluorosilicone

Because of its compatibility with FDA regulations, silicone is a top choice material for the medical industry. In addition to medical applications, silicone can also be found in the automotive, aerospace and electronics industries. Typical applications for silicone include: 

  • Electrical equipment seals in cockpits, automotives and medical devices
  • Engine gaskets and gas turbine seals
  • Hydraulic seals
  • Medical pumps, ventilators, IV components and feeding devices

Fluorosilicone’s distinct resistant properties make it the top choice for the aerospace industry, as well as oil and gas applications. Similarly to silicone, fluorosilicone is often molded into o-rings, gaskets, tubing and other seals. Fluorosilicone is recommended for the following applications:

  • Jet fuel systems
  • Auto fuel emissions control systems
  • Petroleum oil applications
  • Chlorinated solvent environments

Both silicone and fluorosilicone should be used in static seal applications. To learn more about the chemical compatibilities of silicone and fluorosilicone, visit our Chemical Compatibility Guide

Need more information about which material is right for you? 

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