What’s the Difference Between Silicone and EPDM?

Silicone and EPDM (Ethylene Propylene Diene Monomers) are types of rubber that share some truly unique features and uses. Despite this, there are notable differences between them in terms of their properties, which is something to consider when you are choosing between the two.

But Is Silicone better than EPDM? Let’s start with an overview of each, then find out.

EPDM – Ethylene Propylene Diene Monomers is a high density synthetic rubber that is extremely versatile with an ability to withstand high temperatures (up to 215c). Because of this versatility it is used in Automotive, Industrial and several other industries. Within those, EPDM is often used for Seals, O-Rings and Grommets because of its resistant properties against weathering, acids and Alkali’s. Some of EPDM’s key properties include:

guest post

  • Strong acid and Alkali resistance
  • High temperature resistance up to 215c
  • Flame retardant
  • Cost-effective to manufacture
  • Excellent weathering properties
  • Tensile range of 500-2500 P.S.I

Silicone – Silicone is a generally non-reactive, flexible rubber that has interesting properties which make it a widely used material in a number of different industries. Silicone has a high temperature resistance of up to 315c and great flame retardant properties. This makes it ideal for Engineering and Automotive companies. It is also commonly used in the powder coating masking industry, where it is generally utilized for its recyclability and effective heat resistance to mask and protect areas while they are coated and baked. Some of Silicone’s key properties include:

  • High temperature resistance of up to 315c
  • Good flame retardant properties
  • Tensile range of 200-1500 P.S.I
  • Excellent weathering properties

What’s more important to consider before deciding between the two?

When it comes to choosing between EPDM and Silicone, there are multiple factors you should consider to ensure you’re making the best choice for your desired application. For example, you must consider if the material is going to be used outside, then it must have good weathering properties. However, Silicone doesn’t have good acid and Alkali resistance, meaning that if it rains the rubber would be damaged and would be rendered useless. Other factors you need to take in to consideration are:

  • Strength of the material
  • Flexibility
  • Overall costing
  • Resistant properties (chemical, heat, weather, etc.)
  • Weight

Once you have considered each of these factors, you can be sure the material meets all your desired criteria and has the properties you require. There really is no ‘better’ choice of materials when it comes to Silicone and EPDM. When it comes to your requirements, both have a place in the market for industry uses. Therefore, it’s essential you make an informed decision based on price, strength, properties and so on.


 

This post is a guest submission from Vital-Parts, a plastic and rubber component distributor located in Charing, Kent. 

9 Comments


  1. Great post,

    I really appreciate for sharing such information about silicone rubber here, there are many people who is not aware about the use of it.

    keep it up thanks

    Reply

  2. We have an issue on a project where we are now trying to differentiate between supplied epdm and silicone. We have both products in black. Can you offer guidance for a burn / tear test that we can perform to see if the supplied silicone is in fact silicone, and not accidentally supplied with epdm?

    Reply

    1. Hi Steve,

      Thanks for reading our blog post and reaching out about our testing capabilities! I invite you to contact us at info@polymersolutions.com. One of our technical experts can assist you in coming up with the best approach to solve your problem!

      Best wishes,
      Ashlyn Davidson
      Polymer Solutions

      Reply

    2. Hi Steve,

      I had the opportunity to speak with Kyle, our Technical Sales Manager. Here is what he shared:

      “Silicones are generally higher in temperature resistance and one may be able to see a difference in chemical resistance. But chemical resistance differentiation may require some pretty nasty chemicals (HCl, Amyl Alcohol, Ammonium Chloride, Potassium Ethoxide etc.)

      I’m sure that you would see a difference in a burn test, but I don’t know how it would present itself. FTIR is the way to go.”

      Best wishes,
      Ashlyn
      Polymer Solutions

      Reply

  3. This is very handy information. I think epdm is more versatile rubber but i wonder why silicon is more expensive.

    Reply

  4. Really interesting, Thanks for the information.
    Which rubber will not swell or perform better in a fluid containing silicone?
    I once had an issue with silicone rubbers swelling on a liquid solution with silicone, but never knew if the silicone fluid on silicone rubber interaction was the issue. Just changed to EPDM because it is resistant to a wide range of chemicals and is resistant to swelling.

    Reply

  5. silicone has more wide usage. And more flexible in terms of use. This is my opinion

    Reply

  6. I have a 5 th wheeler caravan with a EPDM rubber roof is there any thing you can apply to protect the rubber to prolong the life of the roof
    Thanks Bob

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *