Hydrolyzed Polymaleic Anhydride (PMA-w)


Polymaleic anhydride 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. PMA-w is soluble in water and has a high chemical, and thermal stability. The decomposed temperature is above 330℃.

HPMA-w has an obvious threshold effect under high temperatures (350℃) and high pH values (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 a temperature of 300℃ with an effective time of as long as 100 hours.

CAS No.:


Structure Formula:

Polymaleic Acid structure formula


AppearancePale yellow to umber transparent liquid
Solid content, %48.0 Min.
Bromine value, mg/g80.0 Max.
Average molecular weight, g/mol450 Min.
Density (20℃), g/cm31.18 Min.
pH (1%  solution)2.0-3.0


Due to its good scale inhibition and high-temperature tolerance properties, Hydrolyzed poly maleic 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, PMA-w has a good corrosion inhibition effect when used with zinc salt. It can also be used as an additive for cement.


Hydrolyzed poly maleic anhydride is usually used with organic phosphonate at a dosage of 1~15ppm for circulating cool water systems, oilfield fill water, crude oil dewatering, and low-pressure boilers. PMA-w has good scale inhibition (98%) and scale stripping properties. Combined 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.

200l plastic drum 1000l IBC

Safety Protection:

Acidity, avoid contact with the eyes and the skin. Once contacted, flush with water.


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