dispersant HPMA-structure


Hydrolyzed polymaleic anhydride

CAS No.: 26099-09-2
EC / List No.: 607-861-7
Molecular Formula: (C4H4O4)x

2-Butenedioic acid (2Z)-, homopolymer;
Homopolymer of Maleic Acid;
Hydrolyzed Polymaleic Anhydride (HPMA);
Poly(maleic acid);
Maleic acid, polymers;

Hydrolyzed Polymaleic Anhydride (HPMA), generally with relative molecular weight of 400-800, is non-toxic, easily soluble in water, mainly used as scale inhibitor and dispersant for water treatment, and can be used in high temperature and high alkaline environment.

It is made of maleic anhydride homopolymer, a kind of low molecular weight polymeric electrolyte, easily soluble in water, high chemical stability and thermal stability, resistant to decomposition temperature up to 330℃, because it has a lot of carboxyl functional groups, so it can play a disturbing and destructive role to scale forming substances, make the crystal distortion, and has a strong dispersing and anti-deposition effect to precipitates.

HPMA still has good scale inhibition and dispersion effect on carbonate below 300℃, and the scale inhibition time can reach 100h.

HPMA has good compatibility with organophosphonic acid and quaternary ammonium compounds, and is not affected by chlorine and other oxidizing biocides under normal use conditions.

Technical Data:
Appearance: light yellow to brownish red transparent liquid
Solid content/%: ≥48.0
pH value (1% aqueous solution): 2.0~3.0
Density(20℃)/g*cm-3: ≥1.18
Bromine value/mg*g-1: ≤80.0
Average molecular weight: ≥400 or ≥600


  1. Chelating and dispersing auxiliaries in textile and dyeing auxiliaries.
  2. HPMA is used as scale inhibitor and dispersant in water treatment.
  3. HPMA is used as soil improver and cement additive.

1.Sequestering and dispersing auxiliaries in textile and dyeing auxiliaries

HPMA is used as chelating and dispersing agent in textile dyeing auxiliaries, used as printing and dyeing auxiliaries to soften water quality, as boiling and bleaching process to metal ion complexation; reactive dyestuff, direct dyestuff and reducing dyestuff leveling agent, dispersing agent.

Used as boiling auxiliary can disperse dirt and impurities, chelate and disperse calcium and magnesium ions in boiling liquid; it is conducive to the removal of pectin, prevent the generation of insoluble calcium and magnesium salts and deposition on the fabric, so as to improve the moisture absorption of fiber and wool efficiency.

Used as rinsing agent for textiles, it can reduce the ash content of textiles.

Used as bleaching auxiliary to add chelating dispersant in bleaching solution, it has significant complexing power to calcium, magnesium, iron, copper and other metal ions in the bleaching solution, preventing fabric strength from decreasing and hole generation, and significantly improving whiteness.

When dyeing, adding chelating dispersant can effectively complex the calcium and magnesium ions in the dyeing solution, which has a strong dispersing effect on dyestuff and paint to prevent the precipitation of dyestuff.

2.HPMA is used as scale inhibitor and dispersant in water treatment

HPMA is suitable for high temperature and alkaline water quality or used in combination with other drugs.

HPMA alone is usually used at a concentration of 1mg/L to 15mg/L (1~15ppm), usually compounded with organic phosphate, used in circulating cooling water, oilfield water injection, crude oil dewatering, low-pressure boiler furnace treatment, with good inhibition of scale generation and stripping the role of old scale.

HPMA has a synergistic effect when compounded with zinc salts to prevent corrosion of carbon steel.

HPMA has excellent scale inhibition and high temperature resistance, so it is used in circulating cooling water, oil field water injection, crude oil dewatering, steam locomotive, water and oil pipeline, desalination flash device, low-pressure boiler furnace water and other high water temperature environment, with good scale inhibition or stripping of old scale, often used in combination with organophosphonates. In addition, HPMA has a certain corrosion inhibition effect, and better compounding with zinc salts.

3.HPMA is used as salt and alkali soil improver and cement additive.

Safety and protection
HPMA is acidic, low toxic, corrosive, and can be degraded by microorganisms, and the degraded products are harmless to human, animal and water creatures. Operators should wear protective gloves when working, avoid direct contact with skin, pay attention to labor protection, avoid contact with skin, eyes, etc., and rinse with plenty of water after contact.

Packaging and storage
HPMA is packed in plastic drums, 25kg per drum or as determined by the user. It should be stored in a ventilated place at room temperature, protected from sun and rain, and avoid contact with strong alkaline substances during storage and transportation.

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