Nitrile,Silicon,Viton, Rubber, O ring question if you please.

[barrel]

Have seen O rings described as being made of the aforementioned materials. I always thought a black rubber O ring was just that. Can anyone please explain the differences between the materials and is one more preferable than the other. Many thanks if you can offer an explanation

Kindest regards

Barrel

[oliver13]

There's a bit bit more to it than that, it's quite a big field, I've worked with engineers who specialise in O rings & seals. Google O ring chemical resistance & it will throw up a load of manufacturers tables, like the one from Parker:
http://www.sealingdevices.com/docume...patibility.pdf

Traditionally O rings are destroyed by hydrocarbon/petroleum based lubricants but in practise as illustrated not too many actually are. I use silicone grease on them as exclusively as possible, but probably don't really need too.