Experiment: Butyl Rubber Stoppers + Ovens

A colleague and I did some experimentation.

Goal: Can we determine what level of heat causes butyl rubber stoppers to become compromised?

Methods: We heated stoppers up in the oven at various temps, then tried to core them once they cooled.

Results: DO NOT PUT STOPPERS IN THE OVEN. They off-gas, quite horribly, when approaching dry heat sterilization temperatures (160C). If a stopper was closing a vial, and then that vial was heated in an oven to sterilization temperature, the rubber stopper would off-gas directly into the vial. I’m no chemist, but I’d guess that the vaporized rubber could bind to oil in the preparation.

Stoppers are safe to autoclave but not dry heat sterilize.

Also, we did not successfully core a single vial from this experiment. Either we suck at coring or rubber stoppers hold up pretty good to light heat.