Sodium polyacrylate, also known as waterlock, is a sodium salt of polyacrylic acid with the chemical formula [-CH₂-CH(CO₂Na)-]_n and broad application in consumer products. It has the ability to absorb as much as 200 to 300 times its mass in water. Sodium polyacrylate is an anionic polyelectrolyte with negatively charged carboxylic groups in the main chain. While sodium neutralized polyacrylic acids are the most common form used in industry, there are also other salts available including potassium, lithium and ammonium.

Applications

Sodium polyacrylate and other derivatives of polyacrylic acid have a wide variety of commercial and industrial uses that include:

• Sequestering agents in detergents. By binding hard water elements such as calcium and magnesium, the surfactantsin detergents work more efficiently.
• Thickening agents
• Coatings
• Artificial snow
• Laundry detergent
• Disposable diapers
• Potted plants
• Bath time recreational gel (such as Gellibaff or Squishybaff)
• Super absorbent polymers. These cross-linked acrylic polymers are referred to as "Super Absorbents" and "Water Crystals", and are used in diapers.^[1] Copolymer versions are used in agriculture and other specialty absorbent applications. The origins of super absorbent polymer chemistry trace back to the early 1960s when the U.S. Department of Agriculture developed the first super absorbent polymer materials.^[2] This chemical is featured in theMaximum Absorbency Garment used by NASA.
• Personal lubricant