Sodium polyacrylate (also called acrylic sodium salt polymer) is a superabsorbent polymer that is used extensively in commercial applications as a water absorbent. It is a white, granular, odorless solid that is not considered hazardous. Sodium polyacrylate is made when a mixture of acrylic acid and sodium acrylate is polymerized.
Sodium polyacrylate is used as a thickening agent in industrial processes and to dissolve soaps. A thickener increases the viscosity of hydro-based systems, increases its stability, and provides body without modifying its other properties. Sodium polyacrylate behaves as a wetting and dispersing agent, promoting miscibility and facilitating even dispersion. Sodium polyacrylate acts as a sequestering (or chelating) agent in many detergents. It acts by combining with dissolved substances in water and binding them together, allowing detergent surfactants (wetting agents) to act effectively.
Sodium polyacrylate is added to potted plants and soils to allow them to retain moisture. It behaves as a water reservoir, soaking up excess water and discharging it when required. Florists use sodium polyacrylate to preserve water and help retain the freshness of flowers.
Baby and Feminine Products
Diapers are made absorbent by the addition of a thin membrane of sodium polyacrylate. The outermost layer of a diaper is made of microporous polyethylene, and the innermost layer is polypropylene. Polyethylene keeps the urine from leaking, and polypropylene absorbs moisture from the skin and allows the diaper to keep dry and soft. Between these two layers is a layer of sodium polyacrylate in combination with cellulose. According to “Chemistry & Chemical Reactivity, Volume 2,” sodium polyacrylate can easily absorb up to 800 times its weight in water. Sodium polyacrylate is also used in tampons and similar female hygiene products.
Sodium polyacrylate is used in surgical sponges that wipe away harmful spills.
Sodium polyacrylate is added to gas containers (jet fuel, diesel, and gasoline) to absorb water. It is used in filtration units that separate water from automobile and airplane fuel, increasing the efficiency of the vehicle.
Sodium polyacrylate protects electrical and optical cables from moisture. It is applied to the conductor or shielding of communication and power cables. Sodium polyacrylate blocks water from penetrating and damaging a cable.
- cable image by Yuri Tuchkov from Fotolia.com