Carbomer 940 is a high molecular weight, crosslinked polyacrylic acid polymer. It is commonly used as a thickening, suspending, and emulsifying agent in pharmaceuticals, cosmetics, and personal care products. Carbomer 940 is known for its ability to create transparent gels and has a wide range of applications due to its versatility.
Chemical Structure:
Carbomer 940 is a synthetic polymer that consists of acrylic acid monomers crosslinked with a polyalkenyl polyether. The crosslinked structure gives it its unique properties, such as the ability to absorb and retain water, which leads to its thickening and gelling abilities.
Physical Properties:
- Appearance: Carbomer 940 is typically supplied as a white, fluffy, and free-flowing powder.
- Solubility: It is not soluble in water but can swell and disperse in water to form a viscous gel. The gel formation occurs when Carbomer 940 absorbs water and swells, increasing its volume and viscosity.
- PH Sensitivity: The effectiveness of Carbomer 940 as a thickening agent is influenced by the pH of the solution. It is most effective in formulations with a pH range of around 5 to 10.
- Viscosity: Carbomer 940 is well-known for its high viscosity at low concentrations. It can create thick gels and increase the viscosity of liquids, providing stability to suspensions and emulsions.
- Transparency: One of the notable features of Carbomer 940 is its ability to create transparent or translucent gels, making it suitable for clear formulations in cosmetics and pharmaceuticals.
- Rheological Properties: Carbomer 940 imparts pseudoplastic flow behavior, meaning its viscosity decreases with shear force. This property makes it easy to spread and apply while still maintaining thickness when at rest.
- Stability: Carbomer 940 is stable over a wide range of temperatures and is compatible with many other ingredients commonly used in cosmetic and pharmaceutical formulations.
- Hydration and Swelling: When Carbomer 940 comes into contact with water, it swells and absorbs water, leading to gel formation. The extent of swelling affects the final viscosity of the gel.
It’s important to note that the properties of formulations containing Carbomer 940 can vary based on factors such as concentration, pH, other ingredients in the formulation, and the specific application. As with any ingredient, it’s essential to follow recommended usage guidelines and conduct compatibility and stability tests when formulating products.