Polymaleic acid
[CAS# 26099-09-2]

Identification

• Classification: Catalysts and additives >> Polymer
• Name: Polymaleic acid
• Synonyms: (Z)-2-Butenedioic acid homopolymer; Hydrolyzed polymaleic anhydride; HPMA; PMA
• Molecular Formula: (C₄H₄O₄)_n
• CAS Registry Number: 26099-09-2
• EC Number: 607-861-7
• SMILES: C(=CC(=O)O)C(=O)O

Properties

• Density: 1.18 (48% aq.)

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H290-H314-H318-H319
• Safety Statements: P234-P260-P264-P264+P265-P280-P301+P330+P331-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P321-P337+P317-P363-P390-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1	H314
Skin corrosion	Skin Corr.	1B	H314
Skin irritation	Skin Irrit.	2	H315
Skin corrosion	Skin Corr.	1A	H314
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - single exposure	STOT SE	3	H371

• Transport Information: UN 3265

Discovery and Applications

Polymaleic acid, a synthetic polymer derived from maleic anhydride, has become a significant chemical in industrial and environmental applications. The discovery of polymaleic acid is linked to the growing interest in polycarboxylic acids during the mid-20th century when research efforts focused on developing water-soluble polymers for various uses. As a polymer of maleic acid, polymaleic acid exhibits unique properties such as high dispersing ability and chelating power, which have made it valuable in fields like water treatment, scale inhibition, and as an additive in industrial processes.

The chemical structure of polymaleic acid consists of repeating units of maleic acid, connected through covalent bonds that form the polymer backbone. This structure imparts the polymer with multiple carboxylic acid groups along the chain, which can dissociate in water, making the compound highly effective in binding to metal ions and other substances. The water solubility and dispersing capability of polymaleic acid are key to its widespread application in various industries.

One of the primary applications of polymaleic acid is in water treatment, where it is used as a scale inhibitor. Hard water, which contains high levels of calcium and magnesium ions, can lead to the formation of mineral scales in pipes, boilers, and other equipment, reducing their efficiency and lifespan. Polymaleic acid prevents this by binding to the metal ions, keeping them in solution and preventing the crystallization that leads to scale formation. This property is particularly valuable in industries that rely on heat exchange systems, such as power plants, petrochemical facilities, and desalination plants.

In addition to scale inhibition, polymaleic acid also functions as a dispersant. It is commonly used in industrial cooling water systems, detergents, and cleaning agents to prevent particles from clumping together, thereby maintaining the efficiency of water flow and heat transfer. The dispersing action of polymaleic acid ensures that suspended particles, such as dirt, minerals, or even pigments, remain evenly distributed in solution. This prevents fouling and blockages in industrial equipment, reducing maintenance costs and extending equipment life.

Another significant application of polymaleic acid is in the formulation of detergents and cleaning agents. Its ability to soften water and prevent the precipitation of calcium and magnesium ions enhances the cleaning performance of these products. In this context, polymaleic acid serves as a chelating agent, binding to the metal ions and preventing them from interfering with the action of surfactants, which are responsible for breaking down grease and dirt. This property makes polymaleic acid a common ingredient in household and industrial cleaning products, especially those designed for use in hard water conditions.

The agricultural sector has also found uses for polymaleic acid, particularly as a soil conditioner and fertilizer additive. The polymer’s chelating properties help bind metal ions in the soil, making essential nutrients like calcium, magnesium, and iron more available to plants. In addition, polymaleic acid improves the retention of water and nutrients in the soil, promoting better plant growth and reducing the need for chemical fertilizers. Its role in enhancing soil structure and nutrient availability is particularly beneficial in areas with poor soil quality or challenging growing conditions.

Despite its broad utility, polymaleic acid presents certain challenges, particularly regarding environmental impact. Being a synthetic polymer, it does not readily biodegrade, raising concerns about its accumulation in water bodies and soils. This has led to ongoing research efforts aimed at developing more sustainable alternatives or methods to improve the biodegradability of polymaleic acid without compromising its effectiveness.

Polymaleic acid’s combination of dispersing ability, chelating power, and scale inhibition properties has made it a vital component in water treatment, cleaning products, and agricultural applications. Its role in maintaining the efficiency of industrial systems and enhancing the performance of cleaning and agricultural products underscores its importance across multiple sectors. Continued advancements in polymer science may lead to even broader applications for polymaleic acid, especially as industries seek to balance performance with environmental sustainability.

References

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