Is this the polyacrylic acid/sodium polyacrylate material? This is the material that has been used in diapers and so forth for many years. When the polyacrylic acid is 50% converted to the sodium salt, it absorbs an immense amount of water.
I have used this as a good chemistry trick. You put enough of this polymer into an opaque bottle. With appropriate patter and so forth, you then ostentatiously pour water into the bottle. Continue your patter long enough for the polymer to soak up all the water. Then you go to dump it over the head of someone - I used to use the teacher as the victim when I did it in my kids' elementary school classes. Everybody thinks they will get soaked - but nothing comes out, because it is all absorbed in the polymer and turned into a gel!