Polymaleic Acid, Hydrolyzed Polymaleic Anhydride


Polymaleic acid is also known as hydrolyzed polymaleic anhydride. It is a low molecular weight polymeride. The average molecular weight is 400-800. It has no toxicity. Polymaleic acid is soluble in water, high chemical, and thermal stability. The decomposed temperature is above 330℃.

Hydrolyzed polymaleic anhydride has an obvious threshold effect under high temperature (350℃) and high pH value (8.3). It is suitable to be used in an alkaline water system or built with agents. It has good scale inhibition against carbonate and phosphate scales under temperature 300℃ with effective time as long as 100 hours.

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Structure Formula:

Polymaleic Acid structure formula


Item Index
Appearance Pale yellow to umber transparent liquid
Solid content, % 48.0 Min.
Bromine value, mg/g 80.0 Max.
Average molecular weight, g/mol 450 Min.
Density (20℃), g/cm3 1.18 Min.
pH (1%  solution) 2.0-3.0


Due to its good scale inhibition and high-temperature tolerance properties, Hydrolyzed polymaleic anhydride is widely used in desalination plants of flash vaporization equipment, low-pressure boiler, steam locomotive, crude oil evaporation, petroleum pipeline, and industrial circulating cool water systems. In addition, polymaleic acid has a good corrosion inhibition effect when used together with zinc salt. It can also be used as additives for cement.


Polymaleic acid is usually used together with organic phosphonate at a dosage of 1-15ppm for circulating cool water systems, oilfield fill water, crude oil dewatering, and low-pressure boilers. Hydrolyzed polymaleic anhydride has good scale inhibition (98%) and scales stripping properties. When used together with zinc salts, it can effectively inhibit carbon steel corrosion.

Packing and Storage:

200L plastic drum,IBC(1000L),customers’ requirement. storage for one year in a shady room and dry place.

Safety Protection:

Acidity, Avoid contact with eye and skin. Once contacted, flush with water.


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