Hydrolyzed Polymaleic Anhydride, Poly Maleic Anhydride


Hydrolyzed polymaleic anhydride is a low molecular weight polymeride, with average molecular weight 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 temperature (350℃) and high pH(8.3) level, suitable to be used in the 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. Due to its good scale inhibition and high-temperature tolerance properties, polymaleic 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 polymaleic anhydride has good corrosion inhibition effect when used together with the zinc salt. Poly maleic anhydride can also be used as additives 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 together with organic phosphonate at a dosage of 1-15 ppm for circulating cool water system, oilfield fill water, crude oil dewatering, and low-pressure boilers.

Poly maleic anhydride has good scale inhibition (98%) and scales stripping properties. When used together 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. Its main advantage is able to reduce the pump pressure required 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 °C.

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, polymaleic 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, flocculant.

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

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 eye and skin. Once contacted, flush with water.