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I am thinking cheap material that can be used between two layers of carton that absorbs water. I want to use air but I still think that there may be other materials available that

  • absorb water
  • can be easily removed when the outer carton layer is damaged

Possible materials

  • carbon (well absorbing)
  • air (cheap and easy)
  • sand (should be bad)

What is cheap material that absorbs water in packaging?

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2 Answers 2

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What you are looking for is most probably silica gel.
http://en.wikipedia.org/wiki/Silica_gel

It is a highly water absorbent material with large surface area. It is often used in packaging as well as in laboratory in desiccators.

You can actually buy it packed or in bulk easily (let me not link explicit offers here). You can regenerate used (old) silica by heating / drying / pumping, so you don't need to buy every single time new one if the old gets less effective.

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You could probably also use Sodium Polyacrylate, which is used in diapers to absorb water. This can absorb up to more than 200 times its weight in water. It comes in little white pellets, lab grade is $9.90 per 100 g (absorbs more than 2 gal) from Carolina Science (Sodium Polyacrylate).

More information can be found at https://en.wikipedia.org/wiki/Sodium_polyacrylate

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  • $\begingroup$ Can you compare it with silica gel? I think it can absorb mre than silica gel but I cannot find a source for the ratio. $\endgroup$ Jul 1, 2017 at 4:50
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    $\begingroup$ Well according to this website silica gel can adsorb about 40% of its weight in water. $\endgroup$ Jul 1, 2017 at 13:13
  • $\begingroup$ Yes, how much then sodium polyacrylate? $\endgroup$ Jul 1, 2017 at 17:07
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    $\begingroup$ About 200 times its weight. (Note: Sodium Polyacrylate expands into a gel-like material while it absorbs water). You might be looking for silica gel as it won't blow the box up if it absorbs too much water. $\endgroup$ Jul 1, 2017 at 22:28

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