Saturday, October 1, 2011

Effect of long-term high pressure CO2 on acrylic

I left my supercritical CO2 chamber charged up with 750 psi liquid CO2 (not supercritical) for about a week. I then depressurized the chamber, and opened it. At first, the acrylic seemed fine with just minor surface crazing. After a few hours, I was surprised to find the acrylic had deformed in a major way and was full of CO2 bubbles. Weird!

5 comments:

Sam Sunners said...
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bogus said...

Is this the same effect as seen when diving and arising too fast from deep water? In this circumstance, the air that has been compressed and went into your blood expands so quickly that your blood might boil, which kills you.
If you let the Co2 out slowly, the deformation could be avoided, it just needs some time to diffuse out of the acrylic again.

Sam Sunners said...
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bogus said...

Hmm. CO2 is quite heavy already. Which gas should not dissolve into acrylic? Wouldn't it be possible to have a pressure regulator that streams out the gas over a period of 10 hours?

Shaddack said...

What about plating the acrylic with glass, creating a diffusion barrier? Sandwiching the thick plastic with thinner glass, gluing it to the plastic in the same way laminated car windowshields are made?

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