Defoamer is a class of chemicals used to reduce the number and stability of bubbles on the surface of a liquid. Based on its chemical properties and uses.


It can be divided into the following main categories:


Organic defoamer
This type of defoamer is usually made of organic substances, such as silicone oil, fatty alcohol, fatty acid salts, etc. It has a good defoaming effect and can effectively destroy the membrane structure of the bubble surface.




Mineral oil defoamer
Mineral oil defoamer is mainly extracted from petroleum, common white oil, liquid paraffin and so on. They have high temperature resistance.




Polymer defoamer
This type of defoamer is mainly made of polymer materials, such as polyvinyl alcohol (PVA), polysiloxane, etc. They have good dispersion and defoaming properties and are suitable for the defoaming needs of various water-based systems and solutions.




Surfactant defoamer
Surfactant Defoaming agents are a class of surfactants that reduce the formation and stabilization of bubbles by reducing the tension on the surface of a liquid. Common surfactant defoamants include non-ionic, anionic and cationic types.




Biological defoamer
This type of defoamer mainly uses substances produced by microbial fermentation, such as enzymes, bacteria and bacteria liquid. They have good biodegradability and environmental friendliness, and are widely used in some special application fields.


Action principle of defoamer


Principle 1: Reducing the surface tension of the foam causes the foam to burst
The oil defoamer is added to the foaming liquid, this kind of defoamer is not easy to dissolve in water, enter the inside of the foam, reduce the surface tension of the foam, because the surface tension around the foam is almost not reduced, forming a pressure difference, so that the reduced part of the surface is pulled and extended by the surrounding, and eventually lead to the collapse of the foam.




Principle 2: Breaking the elasticity of the foam film causes the foam to burst
When defoamer is added to the foaming system, it will disperse in it and prevent the surfactant from stabilizing the elasticity of the foam film, which will destroy the elasticity of the foam film and cause the foam to burst.




Principle 3: Promote liquid membrane drainage
Adding defoamer to the liquid can promote liquid film drainage, which leads to foam rupture. Fast drainage indicates that the foam is not stable enough, so we can also add chemicals that accelerate foam drainage to assist defoamer.




Principle 4: Hydrophobic substances can cause bubbles to burst
When the hydrophobic substance is added to the foaming solution, the hydrophobic substance will be attracted by the hydrophobic end of the surfactant, making the hydrophobic substance become hydrophilic and enter the water phase, thus playing the role of defoaming.




Principle 5: The addition of surfactants causes the foam to burst
We can add some low molecular substances that can be fully mixed with the solution, such as ethanol, propyl alcohol, octanol and other low molecular substances, which can make the bubble surfactant be solubilized to reduce the effective concentration, but also reduce the tightness between the surfactant molecules, thus weakening the stability of the foam, and finally achieve the antifoam effect.




Principle 6: Electrolytes disintegrate the surfactant double electric layer
The stable existence of foam is due to the interaction of the double electric layer of the surfactant of the foam, at which time we can add ordinary electrolytes to disintegrate the double electric layer of the surfactant, and thus play a defoaming effect.