Compatibility of polymers with Carbonic acids

[davidmoul]

High guys,

I'm looking for some compatibility charts for some polymers with carbonic acid (to use these polymers in a wet CO2 environment).

Where can I found these data for:

Polyesterimide?
Epoxys?
Polyimide?

You will certainly tell me it depends of the exact polymer (especially for epoxys), but the idea is to check for general compatibility, and then to look deeper what could be problematic.

Many thanks for our kind help,

David

 

[Pud]

Google??
Matweb??
IDES??
Suppliers???

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

For the first one you probably mean polyetheramide

Regards
Pat
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[Pud]

Could be PEI (polyetherimide)

http://www.ides.com/generics/PEI/PEI_products.htm

H

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Opps. A slip of the tongue. I should have said Polyetherimide.

Regards
Pat
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[davidmoul]

In fact I'm looking for the polyesterimide, which is considerer as a modified polyimide by the manufacturer, and as similar properties in terms of corrosion.

Thank you for your help.

 

[patprimmer]

I see. One of those fancy high temperature rated cable coating resins.

I think DuPont will be your best source of information, that is if they see it as in their interests to provide it.

I have no data, so I can only guess, but carbonic acid is especially weak as an acid, and the ester link is especially sensitive to hydrolysis.

If the in use environment is at a high temperature and humidity, hydrolysis will be an issue. Tests at room temperature will be of little use if you need a long life exposed to carbonic acid at high temperatures.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[davidmoul]

Thank you for your help,

in fact, it is for a CO2 application (99% of CO2, <1ppm of water) at relatively low temperature (40°C) and pressure (3 bar), so there should not be liquid water, so no acid.

Anyway, during the tests phases, the machine can be open for inspection a couple of time, getting humidity inside and we already had some surprises on other application. That's why we are checking for this new application.

It doesn't seem to be a big issue. Next step would be practical test in gaz conditions on the different material we have a doubt with.

Thank you for your helpful advices, I feel less lonely!