Sodium polyacrylate, also called super absorbent polymer (SAP), can absorb several times its own weight in liquid. It consists of chains of molecular units called monomers. When water or liquid is added to sodium polyacrylate, it absorbs and swells. It is used both industrially and commercially in a variety of products.
Sodium polyacrylate acts as a sequestering agent in detergents, which means it binds elements in hard water like calcium and magnesium in order to allow the detergents to work better at removing stains and dirt.
Because of its fast absorption of water, sodium polyacrylate can be used industrially in water treatment, as a dust prevention agent and in urban sewage treatment. According to Jiulong Environmental Technology Company, it is able to act as a thickening agent and isolate water from other substances. Rather than dissolving, sodium polyacrylate turns into a gel. The gel can be used as a latex thickener and to strengthen paper products. Industries such as oil drilling, cosmetics and textiles also use sodium polyacrylate.
Sodium polyacrylate acts as a reservoir when added to potted plants and soil by soaking up excess water and releasing it as needed. It is also used by florists to keep flowers fresh for a long time without using dirt or soil.
Gro-Creatures or Gro-Beasts are toys that are shaped like dinosaurs, fish and other animals that "grow" when placed in water, and they are made with sodium polyacrylate. When the toy is put into water, the water is drawn to the sodium polyacrylate by osmosis. It absorbs the water until there is an equal amount of water inside the toy and outside.
Sodium polyacrylate is also used to make fake snow. According to the American Chemical Society's document "Hollywood's Special Effects," real snow isn't ideal for filmmaking because once it's been trampled a couple of times it's essentially gone, allowing filmmakers only a few takes before they have to move to a new location or bring in more snow, which is time consuming and expensive. Using fake snow made from sodium polyacrylate allows them to take the time they need and because it expands when water is added, it's easily transported in large amounts.
Diapers and Feminine Hygiene Products
Most diapers are given absorbency with a thin layer of sodium polyacrylate. Typically, it is used in a granular form and helps the diaper retain moisture, allowing it to be thinner with less pine fluff pulp, which is the cushiony substance you see in diapers. Because of this, sodium polyacrylate is used in the same way in tampons and many sanitary pads. Manufacturers can make them relatively thin or compact because sodium polyacrylate is so absorbent. Sodium polyacrylate is also used in surgical sponges because it enables them to wipe up potentially hazardous spills quickly.
Sodium polyacrylate is added to fuel tanks or containers to absorb any water that may have got inside, which aids in making vehicles like planes and cars run more efficiently.
Sodium polyacrylate is applied to the conductor of communication and electrical cables to protect them from water. It works by blocking water and stopping it from reaching the cable where it might cause damage or malfunction.
- American Chemical Society: Hollywood's Special Effects: How'd They Do That?
- Howard Debeck Elementary School: Mr. Thackwray's Science Unit: Science Activity---Where's the Water?
- Jiulong Environmental Technology Co., Ltd.: Sodium Polyacrylate
- The Diaper Industry Source: What Are the Components of a Typical Disposable Diaper?