Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here




Hi All,

I have been testing a peroxide cured EPDM material as a o-ring seal in a high humidity environment. I'm finding leaks in some materials aged at temperatures of 40 degrees C. I've had a look at these samples with SEM and can see cracking on the surface of failed samples and using DSC have seen an exotherm at ~180 degrees C in same samples. I have also noticed significant drops in creep resistance under compression.

~I figured perhaps I wasn't curing the material correctly, but cant find any evidence of an exotherm straght after curing.

Has anyone experience of EPDM degradation at high humidity/temps of 40 degreeC


No, and it's usually a very stable, high set-resistant material, as compared to a sulfur cured version. Is there any chance that there is some hydrocarbon (oil, grease, wax) contaminant getting onto the seals?


Ya that's what i was thinking. No I can't find any evidence of contamination.


I think the 180C exotherm is the evidence...the question is more: what possible source of hydrocarbons, solvents, etc. could be causing it? Think both liquids and vapors.

FWIW, I had a long struggle with a new EPDM diaphragm seal degradation in hot water testing. We never really found the source, but worked hard to fully clean and degrease the test system piping, and to eliminate things like bladder tanks with butyl rubber seals, eventually the problem "dried up".

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close