Sciencemadness Discussion Board

Super absorbent polymers - absorb 400x weight in water - desiccant uses?

RogueRose - 21-3-2017 at 14:38

I came across some of this stuff at a yard sale it's meant to fill the base of sporting items that use water like baskeball poles, punching bags, etc as it turns into a gel.

I think this site has a very similar product (if not the same) - it looks like the type "S" in the pics. SAP polymers site - M2

Here is a link to super absorbent polymers on Wiki - doesn't really say much about specific uses just generalizations.

The package says it polymers and "anti-microbials" in it. I'm wondering if it could be used for removing water from ethanol or from other materials.

If anyone has used this stuff I'd be interested hearing what you have done with it.

I've seen some crystals that are used to replace soil for plants but they don't absorb nearly as much as these do, maybe by a factor of 10 or so.

j_sum1 - 21-3-2017 at 14:59

Lots of uses. Sodium polyacetate is used in disposable nappies (diapers for this in the US). Also to form gel beads for floral arrangements etc.
I think the problem that you would have is that they are not specific to water. They will absorb just about anything. (Exaggeration, but ethanol certainly included.) These kinds of polymers probably have many potential applications in a home lab but desiccating solvents is not one of these.

RogueRose - 21-3-2017 at 17:34

Quote: Originally posted by j_sum1  
Lots of uses. Sodium polyacetate is used in disposable nappies (diapers for this in the US). Also to form gel beads for floral arrangements etc.
I think the problem that you would have is that they are not specific to water. They will absorb just about anything. (Exaggeration, but ethanol certainly included.) These kinds of polymers probably have many potential applications in a home lab but desiccating solvents is not one of these.


Thanks, so it is most likely sodium polyacetate? Is this different han what is used to grow plants? This stuff seems pretty expensive for that. I had seen the plant stuff like 25 years ago and I thought it absorbed like 40x it's weight, this stuff absorbs about 400x.

Would it work as a desiccant in a sealed chamber in place of something like CaCl2 or other desiccant like that? I'm not sure if it will absorb from the air but it sure works fast when water is dropped on it. I'll have to see how it de-hydrates for re-use.

Can it be made at home and is it made form sodium acetate?

[Edited on 22-3-2017 by RogueRose]

macckone - 21-3-2017 at 20:02

This stuff will absorb a lot of water and other stuff but
it is not a desiccant. It won't pull water out of other
substances very well. It utilizes both capillary action
and molecular hydration to absorb water.

Most of these are sodium polyacrylate not polyacetate.