Carbomer 940: An Analysis of a Classic Polymer Material

In the fields of daily chemicals, skincare, and pharmaceutical preparations, carbomer 940 stands as an indispensable auxiliary material due to its exceptional thickening, emulsifying, and suspending properties. It appears as a loose white powder with strong hygroscopicity, often requiring only small amounts (typically 0.2%–1%) to significantly modulate the rheological characteristics of products. This article will delve into its chemical composition, structural features, and mechanisms of action to help readers gain a deeper understanding of this classic material.

1, Basic chemical composition

Carbopol 940 belongs to cross-linked polymer, and its chemical essence is a cross-linked copolymer of poly (alkyl sucrose) or poly (alkyl pentaerythritol) with acrylic acid. Although the final product exists in a polymerized form, its raw material monomers mainly come from acrylic acid and its derivatives. In the dry powder state, the polymer molecular chains are tightly coiled; Once in contact with water, the molecular chains gradually stretch and form a hydrated structure with water molecules, thereby significantly increasing the viscosity of the system. By adding neutralizing agents such as sodium hydroxide or organic amines, the molecular chains can be further stretched to achieve a more significant thickening effect.

Carbopol 粉末

2, Molecular structure and acid-base properties

From a molecular structure perspective, each repeating unit of Carbopol 940 carries a carboxyl group, making it weakly acidic as a whole, with lower acidity than acetic acid. After dissolving in water, the pH of the system is usually between 2.5-3.5, and as the concentration of carbomer increases, the density of carboxyl groups increases, and the acidity of the solution correspondingly increases. When undergoing neutralization reaction with alkaline substances, carboxyl groups ionize and carry negative charges. Due to repulsion of the same charge, the molecular chain can be greatly extended. When the pH of the system is adjusted to the range of 5-9, the polymer can expand by about a thousand times and increase in diameter by about ten times, thus exhibiting a much higher thickening efficiency than common thickeners.

3, Dissolution and thickening mechanism

The thickening effect of Carbopol 940 is closely related to its dissolution state and molecular conformation. In aquatic systems, molecular chains gradually unfold through hydration, and the viscosity of the system increases accordingly. If polyhydroxy alcohols (such as glycerol) or polyethylene based solvents are used instead of water, carbomer can still bind to solvent molecules through hydrogen bonding, resulting in significant thickening and suspension ability, without the need for additional neutralizing agents. This characteristic makes it suitable for both anhydrous and low water formulations.

4, Key points to note in application

In practical applications, the amount of Carbopol 940 added needs to be adjusted according to the final dosage form. Generally speaking, the lotion system needs less addition, while the gel product needs to increase the proportion appropriately. Due to its high efficiency, excessive use may lead to the system becoming too viscous or unstable. In addition, during the preparation process, it is recommended to first evenly disperse the carbomer powder in the aqueous phase, and then slowly add a neutralizing agent to avoid local agglomeration or uneven neutralization. When storing, attention should also be paid to moisture prevention to ensure the flowability and dispersibility of the powder.

In summary, as a classic polymer material, Carbopol 940's thickening, emulsification, and suspension functions are derived from its specific chemical structure and the stretching behavior of molecular chains in water or polyols. By adjusting the pH and formula process reasonably, it can play a stable and efficient role in various daily chemical, skincare, and pharmaceutical products. Understanding its composition and characteristics helps to better grasp the ratio and process in the application process, achieving ideal formulation effects.

Product packaging

The carbomer sold by Hubei Xindesheng Material Technology Co., Ltd. is a very fluffy white powder substance that becomes a viscous transparent substance after preparation. Adding it to various skincare products not only does not affect its effectiveness or appearance, but also has certain benefits. If you have any relevant procurement needs, please click on our official website to learn more details or contact us!