Best polymer against corrosive fluid and with low permeability?

[Felipe28]

Hello,

I have 2 interesting questios, I believe, regarding polymer properties. I am designing a ball (pretty much like a basketball in size and appearance) to be used inside pressure vessels for certain corrosive fluids. The ball is inflated with air to a certain pressure in order to cushion extreme pressures in the pipeline (water-hammer). These balls will expand and contract according to pressure drops or pressure rises in water, respectively.

1) First question: These balls be in contact with certain corrosive fluids (under pressure) so I am looking for any or many polymers to be used as the external layer of the ball, so that it does not suffer from exposion to these special corrosive fluids. I have chemical properties of some of them, but I first ask this for any general corrosive fluid, not one in specific.

2) Second question: So far, I have been using polybutadiene as external polymer in the ball and butyl rubber as internal layer, but I believe there could be better choices in terms of lower permeability, as long as the other options can also be moulded and used as the external layer in a ball, for a reasonable cost (i.e, commercial polymers). The idea is to find also a polymer that can hold for a longer time the air inside the ball.

Regards

Felipe

 

[GrahamBennett]

First of all, it would help us to help you if you can identify the corrosive fluids please. For example, are they concentrated alkalis or mineral acids, or are they organic solvents, etc.

Secondly, good alternatives to butyl rubber would be either chlorobutyl or bromobutyl. Both of these exhibit similar levels of impermeability as butyl but are much faster curing, which would be an advantage in co-curing with butadiene rubber.

 

[tom1953]

Felipe, your post is a duplicate of one in the Polymer Engineering forum