2- propenoic acid, homopolymer, sodium salt, sulfonated: properties, uses, pros, cons, safety

2- propenoic acid, homopolymer, sodium salt, sulfonated is Sodium polyachrylate sulfonated, a water-soluble, high molecular weight compound with high rigidity and viscosity in its aqueous solution.

It is a synthetic polymer derived from propenoic acid (acrylic acid) and modified with sulfonate groups. It is primarily used as a dispersing agent, thickener, and stabilizer in a wide range of industrial and cosmetic applications. The polymer is known for its ability to stabilize formulations and improve the distribution of ingredients within aqueous solutions.

Chemical Composition and Structure
2-Propenoic acid (acrylic acid) is polymerized to form a homopolymer, which is then neutralized with sodium and modified with sulfonate groups. The presence of sulfonate groups gives the polymer hydrophilic properties and allows it to bind with water, making it highly soluble in aqueous environments. This structure makes it ideal for use in formulations requiring stability and dispersing capabilities.

Physical Properties
The sulfonated polymer of 2-propenoic acid typically appears as a powder or viscous liquid, easily soluble in water. It increases the viscosity of solutions and acts as a dispersing agent, stabilizing suspensions and improving the uniform distribution of ingredients.

Production Process
The polymer is produced through the polymerization of 2-propenoic acid, followed by neutralization with sodium and sulfonation. This chemical process creates a product that has both thickening and dispersing properties, making it useful in a wide variety of industrial and cosmetic applications.

The name describes the structure of the molecule:

• "2-propenoic acid" is most commonly known as acrylic acid. It is an organic compound with the formula CH₂ = CHCOOH and is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminal.
• "Homopolymer" refers to a polymer consisting of one type of monomer. In this case, the monomer is 2-propenoic acid.
• "Sodium salt" indicates that the hydrogen atom in the carboxylic acid group of 2-propenoic acid has been replaced with a sodium ion. This is a common way to make carboxylic acids more soluble in water.
• "Sulfonated" refers to the process of adding the sulfonate group to a molecule. Sulfonate (-SO3-) groups are typically added to improve the solubility of a compound in water.

Description of raw materials used in production

• 2-propenoic acid (acrylic acid) - A liquid monomer that can be polymerized to form poly(acrylic acid).
• Sodium hydroxide (NaOH) - Used to neutralize the poly(acrylic acid) and form its sodium salt.
• Sulfonating agents - Compounds like sulfur trioxide (SO₃) can be used for sulfonation.

The synthesis process takes place in several stages:

• Polymerization of 2- propenoic acid. In this phase, polymerization of 2- propenoic acid develops to form homopolymer. This is typically done using a free radical initiator, which begins the polymerization reaction.
• Formation of sodium salt. Reaction of carboxylic acid groups in the polymer with sodium hydroxide (NaOH). Sodium ions replace hydrogen ions in carboxylic acid groups, forming the polymer’s sodium salt.
• Sulfonation. The final step is the sulfonation of the polymer. Reaction of the polymer with sulfur trioxide (SO₃), which adds sulfonate groups to the polymer. Sulfonate groups improve the water solubility of the polymer, making it more useful in applications such as detergents and surfactants.

Applications

• Cosmetics: In detergents, which has the function of thickener, it has the characteristic of binding to magnesium and calcium, favoring the action of surfactants.

• Skincare and Haircare: Used in products such as gels, creams, and lotions for its thickening and stabilizing properties. It helps maintain the consistency of products and improves the distribution of active ingredients on the skin or hair.

• Detergents: Used in detergent formulations to enhance the stability of suspensions and the dispersion of particles, ensuring effective cleaning.

• Industrial Products: Utilized as a dispersing agent in paints, coatings, and other industrial formulations to improve particle distribution and prevent sedimentation.

Health and Safety Considerations

Safety in Use
2-Propenoic Acid, Homopolymer, Sodium Salt, Sulfonated is considered safe for use in cosmetic and industrial products. It is generally well tolerated by the skin and is not known to cause significant irritation or allergic reactions. However, as with any chemical ingredient, it should be used within the recommended concentrations.

Allergic Reactions
Allergic reactions to this polymer are rare. However, for individuals with very sensitive skin, it is advisable to perform a patch test before using products containing this ingredient.

Toxicity and Carcinogenicity
There is no evidence that the polymer of 2-propenoic acid, sodium salt, is toxic or carcinogenic. It is widely used in cosmetic and industrial products without known health risks.

Environmental and Safety Considerations
The polymer is synthetic and non-biodegradable, meaning it can accumulate in the environment. It is important that products containing this ingredient are disposed of properly to minimize environmental impact.

Regulatory Status
2-Propenoic Acid, Homopolymer, Sodium Salt, Sulfonated is approved for use in many regions, including the European Union and the United States. Regulations ensure that it is used in safe concentrations in both cosmetic and industrial products.

Studies

Medicine

• In the present study, preventive effects of Sodium polyacrylate (PANa) on three kinds of esophageal lesions induced by gastric juice were examined in comparison with those of aceglutamide aluminium and sodium alginate. The influences of PANa on gastric contents were also studied. The preventive effect of PANa given intraesophageally on esophageal lesions induced by the intraesophageal application of gastric juice was more potent than aceglutamide aluminium and sodium alginate. Oral administration of PANa inhibited the formation of esophageal ulcer by pylorus ligation more markedly than aceglutamide aluminium, whereas sodium alginate had no effect in a high dose of 500 mg/kg. In preventing gastric ulcer which occurred simultaneously with the esophageal ulcer after the pylorus ligation, aceglutamide aluminium was most potent, and PANa was as potent as sodium alginate. Oral administration of PANa showed a more protective effect than aceglutamide aluminium on the esophageal ulceration induced by the simultaneous ligations of the pylorus and limiting ridge, whereas sodium alginate in a high dose of 500 mg/kg had little effect on the ulcer formation. PANa caused only a slight increase in the pH of gastric juice and a slight decrease in pepsin activity. From these results, it may be concluded that PANa showed an antiulcerogenic activity mainly due to its mucosa covering action against gastric juice (1).
• Available methods for postoperative adhesion prevention are insufficient. A previous study demonstrated that LM-200, a bioadhesive cellulose derivative was effective in reducing adhesions. Increasing the viscosity of a polymer solution enhances the tissue separating properties. Theoretically, a combination of sodium polyacrylate (PA) and LM-200 would give more viscous solutions than LM-200 alone, and thus be more efficacious. Therefore the efficacy of various combinations of LM-200 and PA was investigated. A lesion was created in the peritoneum of mice. The solutions to be tested, or saline, were given intraperitoneally. One week post-operatively, adhesion formation was quantified and expressed as a percentage of the original lesion covered with adhesions. PA (0.01 and 0.03 wt%) given separately did not differ in adhesion reducing effect from LM-200 (p = 0.3710 and 0.3481) but PA (0.1 wt%) resulted in significantly less adhesion formation (p = 0.0004). The effect of LM-200 increased significantly when adding PA (0.01 wt%) (p = 0.0007) or PA (0.03 wt%) (p < 0.0001). When adding PA (0.1 wt%) the effect was even more pronounced (p < 0.0001). The combination of a bioadhesive cellulose derivative and the polymer PA, was effective in reducing postoperative adhesion formation and a dose-dependent increase in efficacy was obtained compared to using the two components separately (2).

Industry

• Self-healing solid-state aqueous rechargeable NiCo||Zn batteries are inherently safe and have a high energy density and mechanical robustness. However, the self-healability of solid-state batteries has only been realized by a few studies in which electron/ion-inactive self-healable substrates are utilized. This arises from the lack of self-healable electrolytes. Now an intrinsically self-healing battery has been designed that utilizes a new electrolyte that is intrinsically self-healable. Sodium polyacrylate hydrogel chains are crosslinked by ferric ions to promote dynamic reconstruction of an integral network. These non-covalent crosslinkers can form ionic bonds to reconnect damaged surfaces when the hydrogel is cut off, providing an ultimate solution to the intrinsic self-healability problem of batteries. As a result, this NiCo||Zn battery with this hydrogel electrolyte can be autonomically self-healed with over 87 % of capacity retained after 4 cycles of breaking/healing. (3).

Molecular formula: C₃H₃NaO₂

CAS: 95077-68-2

Synonyms :

• 2-Propenoic acid, sodium salt
• Acrylic acid polymer, sodium salt
• Acrylic acid, sodium salt
• carbomer
• carbopol
• HSDB 6087
• LS-145 553
• Polyco
• Sodium polyacrylate
• Sodium poly acrylate
• Polyacrylate sodium salt
• Polyacrylic acid, sodium salt

References__________________________________________________________________

(1) Nakamura K, Ozawa Y, Furuta Y, Miyazaki H. Effects of sodium polyacrylate (PANa) on acute esophagitis by gastric juice in rats. Jpn J Pharmacol. 1982 Jun;32(3):445-56. doi: 10.1254/jjp.32.445. PMID: 7109349.

Abstract. Sodium polyacrylate (PANa) is a water-soluble, high-molecular compound, and its aqueous solution shows a very high viscosity and stringiness. In the present study, preventive effects of PANa on three kinds of esophageal lesions induced by gastric juice were examined in comparison with those of aceglutamide aluminum and sodium alginate. The influences of PANa on gastric contents were also studied. The preventive effect of PANa given intraesophageally on esophageal lesions induced by the intraesophageal application of gastric juice was more potent than aceglutamide aluminum and sodium alginate. Oral administration of PANa inhibited the formation of esophageal ulcer by pylorus ligation more markedly than aceglutamide aluminum, whereas sodium alginate had no effect in a high dose of 500 mg/kg. In preventing gastric ulcer which occurred simultaneously with the esophageal ulcer after the pylorus ligation, aceglutamide aluminum was most potent, and PANa was as potent as sodium alginate. Oral administration of PANa showed a more protective effect than aceglutamide aluminum on the esophageal ulceration induced by the simultaneous ligations of the pylorus and limiting ridge, whereas sodium alginate in a high dose of 500 mg/kg had little effect on the ulcer formation. PANa caused only a slight increase in the pH of gastric juice and a slight decrease in pepsin activity. From the results, it may be concluded that PANa showed an antiulcerogenic activity mainly due to its mucosa covering action against gastric juice.

(2) Falk K, Lindman B, Bengmark S, Larsson K, Holmdahl L. Sodium polyacrylate potentiates the anti-adhesion effect of a cellulose-derived polymer. Biomaterials. 2001 Aug;22(16):2185-90. doi: 10.1016/s0142-9612(00)00360-4. 

Abstract. Available methods for postoperative adhesion prevention are insufficient. A previous study demonstrated that LM-200, a bioadhesive cellulose derivative was effective in reducing adhesions. Increasing the viscosity of a polymer solution enhances the tissue separating properties. Theoretically, a combination of sodium polyacrylate (PA) and LM-200 would give more viscous solutions than LM-200 alone, and thus be more efficacious. Therefore the efficacy of various combinations of LM-200 and PA was investigated. A lesion was created in the peritoneum of mice. The solutions to be tested, or saline, were given intraperitoneally. One week post-operatively, adhesion formation was quantified and expressed as a percentage of the original lesion covered with adhesions. PA (0.01 and 0.03 wt%) given separately did not differ in adhesion reducing effect from LM-200 (p = 0.3710 and 0.3481) but PA (0.1 wt%) resulted in significantly less adhesion formation (p = 0.0004). The effect of LM-200 increased significantly when adding PA (0.01 wt%) (p = 0.0007) or PA (0.03 wt%) (p < 0.0001). When adding PA (0.1 wt%) the effect was even more pronounced (p < 0.0001). The combination of a bioadhesive cellulose derivative and the polymer PA, was effective in reducing postoperative adhesion formation and a dose-dependent increase in efficacy was obtained compared to using the two components separately.

(3) Huang Y, Liu J, Wang J, Hu M, Mo F, Liang G, Zhi C. An Intrinsically Self-Healing NiCo||Zn Rechargeable Battery with a Self-Healable Ferric-Ion-Crosslinking Sodium Polyacrylate Hydrogel Electrolyte.  Angew Chem Int Ed Engl. 2018 Jul 26;57(31):9810-9813. doi: 10.1002/anie.201805618.