What is Sodium Polyacrylate

Sodium polyacrylate, also known as acrylic sodium salt polymer (ASAP), is a polymeric compound containing both hydrophilic and hydrophobic groups and is classified as a polymeric electrolyte.

Sodium polyacrylate is a white sodium polyacrylate powder, odorless and tasteless, with strong hygroscopic properties. It dissolves slowly in water to form an extremely viscous, transparent liquid. The viscosity of a 0.5% solution is approximately 1 Pa·s. It coagulates at a pH of around 4, dissolves at a pH of around 2.5, and precipitates when the pH falls below 4. Heat treatment, neutral salts, and organic acids have minimal effect on the viscosity of sodium polyacrylate, whereas its viscosity increases under alkaline conditions. It is insoluble in organic solvents such as ethanol and acetone, does not decompose when heated to 300°C, and forms insoluble salts upon contact with divalent or higher metal ions, causing gelation and precipitation.

Sodium Polyacrylate Properties

Sodium Polyacrylate Formula

Applications of Sodium Polyacrylate

Diaper Sodium Polyacrylate

Sodium polyacrylate, produced by the reaction of sodium acrylate, is a linear molecule. If we add special molecules called crosslinking agents to the reaction—molecules whose ends can each react with a sodium polyacrylate molecule—then these two sodium polyacrylate molecules are linked together. If there are enough cross-linking agents, numerous sodium polyacrylate molecules are linked together to form a network structure, much like many strands of yarn woven into a sweater. The resulting sodium polyacrylate can be used to produce disposable diapers.

So how does sodium polyacrylate play a key role in disposable diapers?

The function of sodium polyacrylate in disposable diapers is to firmly absorb moisture from urine, keeping the baby's skin and clothes clean and dry. In the current production process of disposable diapers, sodium polyacrylate is generally mixed with fibrous materials such as wood pulp to form a sandwich. The role of wood pulp is to help sodium polyacrylate maintain a fixed shape. Afterwards, the interlayer containing sodium polyacrylate will be wrapped in suitable fabric, with the side facing the baby's skin usually made of porous fabric, while the other side of the fabric is made of impermeable material. In this way, after the baby's urine flows onto the diaper, it will penetrate through the holes in the fabric and be absorbed by sodium polyacrylate.

The molecular framework of sodium polyacrylate possesses a certain degree of elasticity. When dry, the molecules are in a contracted state, but once they come into contact with water molecules, they continuously unfold, much like a ball of yarn that has been curled up being gradually straightened out. As a result, the entire network continuously expands, and water molecules continuously enter to occupy the new spaces formed by the expanding network. Eventually, we observe that the added water ceases to flow and instead forms a solid together with the sodium polyacrylate molecules. We refer to this solid as a gel.

Fake Snow Sodium Polyacrylate/Instant Snow Sodium Polyacrylate

When sodium polyacrylate powder comes into contact with water, it rapidly absorbs hundreds of times its own weight in water, causing the powder to swell and take on a fluffy, snow-like texture.

Thickener

In food applications, sodium polyacrylate enhances the binding strength of proteins in flour, causing starch particles to bind together and disperse into the protein network, thereby forming a dense, stable dough gel. This prevents the leaching of soluble starch and results in a smooth, glossy dough surface. Sodium polyacrylate also possesses strong water-retention properties, helping to evenly distribute moisture within the dough and prevent drying; Sodium polyacrylate interacts with proteins to alter their structure, enhancing the viscoelasticity of food products and improving their texture.

Why Choose Kerton Chemicals for Sodium Polyacrylate？

When sourcing high-quality sodium polyacrylate and other industrial chemicals, Kerton Chemicals (Zhengzhou Kerton Chemical Co., Ltd) stands out as your reliable global partner. With decades of experience in chemical R&D, production, and global supply, we deliver consistent quality, tailored solutions, and end-to-end support for your business.