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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.

For example, one of the fluids have the following characteristics:

Temperature is 20°C. I have some information:

- Sulfate concentration: 5.000 mg/l
- Sodium concentration: 18.000 mg/l
- Chlorure concentration: 18.000 mg/l
- Disolved solids: 65.000 mg/l


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 or internal layer in a ball, for a reasonable cost (i.e, commercial polymers). The idea is to find a polymer that can hold for a longer time the air inside the ball. I have seen that rubber polymers (especially butyl) have low permeability properties but that there might be better options?

Regards

Felipe