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!
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Interesting. A similar thing happened to the rubber o-rings in my paintball gun. When I took it apart, they expanded to about 1.5 times their normal size. After a couple hours, they shrunk back to normal size.
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.
@bogus, I don't imagine you could release the pressure slowly enough to stop if from deforming. But if you pressurized it with a gas that doesn't dissolve into acrylic, the CO2 might diffuse out into the other gas.
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?
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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