Sodium polyacrylate, also known as waterlock, is a sodium salt of polyacrylic acid with the chemical formula [−CH2−CH(CO2Na)−]n and has broad applications in consumer products. This super-absorbent polymer (SAP) has the ability to absorb 100 to 1000 times its mass in water.
Sodium polyacrylate is a chemical polymer made up of chains of acrylate compounds. It contains sodium, which gives it the ability to absorb large amounts of water. Sodium polyacrylate is also classified as an anionic polyelectrolyte. When dissolved in water, it forms a thick and transparent solution due to the ionic interactions of the molecules. Sodium polyacrylate has many favorable mechanical properties.
Some of these advantages include good mechanical stability, high heat resistance, and strong hydration. It has been used as an additive for food products including bread, juice, and ice cream.
In addition, sodium polyacrylate is used in paper diapers and Maximum Absorbency Garments as the absorbent material. It is also used in ice packs to convert the water used as the cooling agent into a gel, in order to reduce spillage in case the ice pack leaks. Also, it is used for eco-engineering as a water-retaining agent in rocky slopes for increasing moisture availability in the soil. This can improve the water retention availability of the soil and infiltration capacity in sandy soil.
Below is a table containing categories and lists of some products and applications that utilize sodium polyacrylate.
Sodium Polyacrylate Applications Overview
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Sodium polyacrylate itself does not irritate the skin.It is made up of large polymers that do not have the ability to infiltrate the skin. However, sometimes sodium polyacrylate is mixed with acrylic acid which is leftover from the manufacturing process. As a leftover of producing sodium polyacrylate, acrylic acid can cause a rash in contact with skin. It should be less than 300 PPM as the absorbent material in paper diapers.
Also, if sodium polyacrylate is being used in a powder form it should not be inhaled. If spilled in an area with water, sodium polyacrylate could cause the ground to be very slippery. Finally, sodium polyacrylate can cause severe clogging if it enters sewers or drainage systems in large quantities. Otherwise, sodium polyacrylate is non-toxic and safe from any major risks.