A copolymer of acrylamide and acrylic acid (normally supplied as the sodium salt) that is cross-linked sufficiently to render it insoluble in water but which retains its hydrophilic nature. It therefore can absorb a very large amount of water, swelling proportionately as it does so. The amount of water that can be absorbed is typically around 400x the weight of polymer if the water is completely free of solutes, decreasing quite markedly as the level of solute(s) increases. Its applications include horticulture, hygiene products like disposable diapers and inummerable odd jobs around the laboratory. Information provided by Goodfellow. |