Superabsorbent Polymer, Sodium polyacrylate It is a polymer where the long chains are cross-linked to one another. It is a polymer that can absorb water many times its volume therefore earning the term superabsorbent. After it absorbs the water it forms a stiff gel.

Why sodium polyacrylate absorbs water It is a long chained molecule with many repeating units (a polymer). Each of the repeating units has a portion that holds an electrical charge. The electric charges on the polymer attract water molecules and bind them to the polymer. Each charge binds several water molecules and each molecule of polymer can bind a large volume of water.

Procedure Remove cotton-like filling from diaper tear filling into small pieces and put in the plastic bag rub bag in hands to separate the polyacrylate from the cotton put the polyacrylate in a dry beaker removing any visible cotton slowly add liquid into beaker stopping to make sure it is absorbed, continue adding liquid until no more is being absorbed measure the volume of liquid absorbed

Questions Why does something dissolved in the water reduce the amount of water absorbed by the polymer? What are some uses of this material?

Why the salt decreases the amount of water absorbed Like the polymer the salt also contains electrical charges which attract water molecules. Furthermore, the charges in the salt are attracted to the charged parts of the polymer and displace the molecules of water from the polymer.

Other uses of sodium polyacrylate filtering fuels food packaging potting soil alkaline batteries hair gels fire retardants