Hydrolyzed Polymaleic Anhydride, Poly Maleic Anhydride


Hydrolyzed polymaleic anhydride is a low molecular weight polymeride with an average molecular weight of 400-800. No toxicity, soluble in water, high chemical and thermal stability, decomposed temperature above 330℃. Poly maleic anhydride has an obvious threshold effect under high temperatures (350℃) and high pH(8.3) levels, suitable to be used in the 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. Due to its good scale inhibition and high-temperature tolerance properties, poly maleic acid is widely used in the desalination plant of flash vaporization equipment, low-pressure boiler, steam locomotive, crude oil evaporation, petroleum pipeline, and industrial circulating cool water systems.

In addition, hydrolyzed poly maleic anhydride has a good corrosion inhibition effect when used with zinc salt. Poly maleic anhydride can also be used as an additive for cement.

CAS No.:


Structure Formula:

Hydrolyzed Polymaleic Anhydride


AppearancePale yellow to umber transparent liquid
Solid content, %48.0 Min.
Bromine value, mg/g80.0 Max.
Average molecular weight450 Min.
Density (20℃), g/cm31.18 Min.
pH (1% solution)2.0~3.0


Hydrolyzed poly maleic anhydride is usually used with organic phosphonate at 1~15 ppm for circulating cool water systems, oilfield fill water, crude oil dewatering, and low-pressure boilers.

Poly maleic anhydride has good scale inhibition (98%) and scale stripping properties. Combined with zinc salts, it can effectively inhibit carbon steel corrosion.

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Used in Oil Fields and Gas Wells.

In a closed gas well and a cement mud well, 0.01 to 5.0% by weight of polymaleic anhydride is added as a fluidity improver. It also acts as a turbulence inducer. The amount of the auxiliary agent is preferably about 0.1% to 2.0% by dry weight of the cement.

Especially when pumping mud into the required location during the well-sealing operation. Polymaleic anhydride greatly increases the flow rate and turbulence of the mud. The main advantage is that it can reduce the required pump pressure at a specific flow rate. Or get a higher flow rate under a fixed pumping condition.

Used in Daily Chemicals.

Polymaleic anhydride or its hydrolyzate may be added to detergents of sodium dodecylbenzene sulfonate. This can improve the quality of the detergent. Generally, the amount of poly maleic anhydride added is only 2.5%. After the addition, the detergent or soap can prevent the inorganic salt insoluble matter from sinking on the textile when washing the textile. This is especially effective when washing textiles with hard water. This not only saves resources but also improves washing efficiency.

Other Uses.

Reacts with a diamine to form a powder resin which is excellent in thermal stability. The heat resistance of this powder resin can reach 400℃.

It can be used as a dispersing agent for inorganic pigments to increase the fineness of inorganic pigments.

As a soil conditioner, hydrolyzed poly maleic anhydride can improve the alkali field and has a protective effect. This is because it is a polyelectrolyte and is water-absorptive.

In the emulsion suspension polymerization process, poly maleic anhydride can be used as a particle size modifier for the polymer.

Polymaleic anhydride and amine react to form semi amide. Semiamide can be used as a modifier for oil. Such as slurry dispersant, viscosity improver, rust inhibitor, and flocculant.

Polymaleic anhydride of different molecular weights can also be used as thickeners, dispersants, foam stabilizers, suspending agents, etc.

Packing and storage:

200L plastic drum, IBC(1000L), customers’ requirements.

200L plastic drum 1000L IBC

Storage for one year in a shady room and dry place.

Safety Protection:

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