Rubber, and especially synthetic rubber, has a wide spectrum of variants, each with their own strengths, weaknesses, and properties. Because of this getting the specific rubber compounds that fit your unique and specific application is important. When it comes to silicone, in particular, there are variations that offer greater resistance and chemical compatibility properties. Let’s dive into one of them.
Fluorosilicone is a formulation 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 do come at a cost, though, especially when compared to standard commercial-grade silicones. While these two materials do share similarities, they are also quite different. Let’s take a closer look at the pros and cons of fluorosilicone.
Let’s look at the benefits first. Fluorosilicone’s distinct resistant properties make it the preferred choice for the aerospace industry, as well as oil and gas applications. Like silicone, fluorosilicone can be injected and compression-molded, extruded, and calendared into o-rings, gaskets, tubing, and other seals. Because of these superior resistant properties, fluorosilicone is often used in the following applications which tend to be very harsh environments:
- Jet fuel systems
- Automotive fuel emissions control systems
- Petroleum oil applications
- Chlorinated solvent environments
- Applications using reformulated refrigerants
- Broad temperature range environments
As we mentioned in the intro, one of fluorosilicone’s key features is its excellent temperature resistance both on the low and high end of the spectrum, but there are other boons. Here is a list of a few of the useful properties it brings to the table including:
- Temperature resistance of standard compound range from -75°F to 400°F (-60°C to 205°C).
- Hardness ranges from 40 to 80 Shore A.
- Resistance to fuel, oil, solvent, and water with slight swelling.
- Excellent resistance to weather and ozone.
- Maintains its tensile and tear strength in harsh environments
- Remains flexible and rubbery in environments that would literally destroy many similar materials
- Excellent flexibility and compression set resistance.
So, now we’ve looked at some of the benefits of fluorosilicone, but before you make the leap into using fluorosilicone, there are some drawbacks to know about before you start using it. Let’s talk about them.
First, as mentioned above, fluorosilicone is expensive. This is because the synthesis of the fluorosilicone rubber monomer is quite difficult and time-consuming, and the introduction of fluorine-containing groups increases the difficulty of the vulcanization process, which drives the production cost quite high.
Second, fluorosilicone does not do well in environments that need abrasion resistance.
Third, while chemical resistance is a strong feature from the fluorosilicone family of elastomers it does not do as well when resisting against brake fluids, ketones, hydrazine, amines, aldehydes, and ketones.
The specialized and unique properties of fluorosilicone bring with them many of silicone’s benefits while adding resistances to non-polar solvents, fuels, oils, acids, and alkaline chemicals. These benefits make them attractive in the right applications. But before you decide to start using fluorosilicone in your gaskets, o-rings, and other projects, you will want to make sure you use the right materials. So, get in touch with experts in non-metallics to be your guide for your projects.