Carbomer wins the hearts of many people because of its powerful application functions. However, in the process of using, there are always problems like this and occasionally irritate you and make you crazy. If you encounter the following problems, that's great. I hope these can help you solve the problems you have encountered and liberate your hair.
Due to the special structure of carbomer, it is easy to swell in contact with water, and it has strong hydrophilicity. The carbomer of dry powder is very hygroscopic. Like other hygroscopic powders, it should be treated improperly. When thrown into water or other polar solvents, it tends to form agglomerates or is not completely wetted. Other powders will eventually decrease and dissolve after forming agglomerates, but the carbomer will not dissolve easily after forming agglomerates, because once the outer layer of the agglomerates is completely infiltrated, the water will not easily penetrate into the internal dry part.
Gel viscosity problem
Temperature has a certain effect on carbomer gel. As the temperature rises, the kinetic energy of molecular motion increases, and the speed of motion increases. Due to the difference in the volume of gel molecules and water molecules, the movement frequency of the two is inconsistent. As the temperature increases, the hydrogen bond between the gel molecules and the water molecules weakens, and some of the hydrogen bonds are broken, which leads to the system’s failure. The viscosity is reduced. However, this effect is reversible, heating within 100 degrees and then returning to room temperature will restore the viscosity; if heated to 260 degrees, it will decompose completely in half an hour.
There are residual polymerization inhibitors, the type and amount of initiator, and the drying temperature. If the drying temperature is too high, the product is easy to change color. Studies have found that if the drying temperature exceeds 120°C, the product is more or less slightly yellowish. Therefore, drying should be dried under reduced pressure below 80°C.
In some gel products, such as disinfectant and disposable gels, ethanol is often added as an additive in order to increase permeability, corrosion protection, and solubilization, and the content may be as high as about 75%. Carbomer gel is essentially a polymer solution. The reason why the polymer solution is stable is that there is a hydration film on the surface of the particle. The addition of a strong hydrophilic non-electrolyte (such as ethanol) will cause the polymer solution to flocculate. Carbomer ethanol gel is prepared by different operation processes, and the ethanol concentration of the finished product is different. When the ethanol concentration is too high, the finished gel will produce a little opalescence, which reduces the transparency of the gel.
When carbomer dissolves in water to prepare a gel, it is best to soak it in deionized water for 24 hours, and then mechanically stir it for half an hour. Neutralizing carbomer usually uses triethanolamine and EDTA-2Na as gel stabilizers. The presence of the hydration film on the surface of the carbomer gel makes the gel relatively stable. The greater the degree of dissociation of the carboxyl group, the less free water content in the gel, and the less prone to bacteria growth. The degree of hydration of the gel can be judged by the sliding time of the gel on the wall of the beaker. Products with the same viscosity but different hydration speeds indicate that the stability of the gel is different. The stability of the gel can be determined by the degree of hydration. Judge, adjust and control.
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