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