Sodium polyacrylate CAS#9003-04-7
High viscosity and thickening ability — Forms extremely viscous solutions, 15-20 times thicker than CMC or sodium alginate, due to ionic interactions.
Excellent stability — Viscosity remains stable under heat (up to 300°C), neutral salts, and organic acids, ensuring reliable performance.
Resistant to decomposition — Maintains viscosity and chemical stability over long storage periods without breaking down.
Unique response to pH and ions — Viscosity increases in alkaline conditions and is sensitive to acids and metal ions, allowing tailored applications.
Sodium polyacrylate is a white, odorless, and tasteless powder that is highly hygroscopic. It is a high-molecular compound containing both hydrophilic and hydrophobic groups. When dissolved in water, it slowly forms a very viscous, transparent liquid. A 0.5% solution of sodium polyacrylate has a viscosity of about Pa·s, which is not due to water swelling (like CMC or sodium alginate) but is instead a result of the ionic interaction of numerous anionic groups in the molecule, causing the molecular chains to grow and increase the apparent viscosity. This leads to the formation of a high-viscosity solution that is roughly 15-20 times more viscous than CMC or sodium alginate. Its viscosity is relatively stable, unaffected by heating, neutral salts, or organic acids, but it increases in alkaline conditions. Sodium polyacrylate is insoluble in organic solvents such as ethanol and remains stable even when heated up to 300°C. Its viscosity remains largely unchanged over long periods of storage and is resistant to decomposition. However, as an electrolyte, its viscosity is sensitive to acids and metal ions, particularly when exposed to divalent or higher metal ions, without causing decomposition.
Parameters
Density | 1.32 g/mL at 25 °C |
refractive index | n20/D 1.43 |
storage temp. | 2-8°C |
form | powder |
Specific Gravity | 1.23 |
PH Range | 6 - 9 |
Odor | Odorless |
PH | 6-9 |
Hydrolytic Sensitivity | 0: forms stable aqueous solutions |
Stability: | Stable, but moisture sensitive. |
InChI | InChI=1S/C3H4O2/c1-2-3(4)5/h2H,1H2,(H,4,5) |
InChIKey | NIXOWILDQLNWCW-UHFFFAOYSA-N |
SMILES | C(=O)(O)C=C |
EPA Substance Registry System | Sodium polyacrylate (9003-04-7) |
Safety Information
Hazard Codes | Xi |
Risk Statements | 36/37/38-36 |
Safety Statements | 26-36 |
WGK Germany | 3 |
RTECS | WD6826000 |
F | 3 |
TSCA | Yes |
HS Code | 39069090 |
Sodium polyacrylate acts as a scale inhibitor, a builder in detergents, and an aid in soap and detergent processing, while also helping to control water hardness.
It is effective as an absorbent for aqueous spills and serves as a retention and slow-release agent for water.
Furthermore, sodium polyacrylate functions as a suspending agent, stabilizer, and emulsifier.
