Defoamers, also known as antifoams, will produce many harmful foam in the process of industrial production, so defoamers need to be added. It is widely used to remove harmful foam generated in the production process of latex, textile sizing, food fermentation, biomedicine, coating, petrochemical, paper making, industrial cleaning and other industries. So what is the defoaming principle of defoamers? Next, the editor of Jianyi Chemical will introduce each one to you one by one!
1. The local surface tension of foam decreases, causing the foam to burst
The origin is that higher alcohol or vegetable oil is sprinkled on the foam. When it is dissolved into the foam liquid, the surface tension will be significantly reduced. Because these substances generally have low solubility in water, the reduction of surface tension is limited to the local part of foam, while the surface tension around foam has almost no change. The part with reduced surface tension is strongly pulled and extended in all directions, and finally breaks
2. Defoamers can break the elasticity of the membrane and cause bubbles to burst
When defoamer is added to the foam system, it will diffuse to the gas-liquid interface, making it difficult for the surfactant with foam stabilizing effect of dispersant to recover the membrane elasticity.
3. Defoamers can promote the drainage of liquid film, resulting in the bursting of bubbles
The discharge rate of foam can reflect the stability of foam. Adding a substance to accelerate the discharge of foam can also play a role in defoaming.
4. Adding hydrophobic solid particles can cause bubble bursting
Hydrophobic solid particles on the surface of bubbles will attract the hydrophobic end of surfactants, causing the hydrophobic particles to become hydrophilic and enter the water phase, thereby playing a role in defoaming.
5. Solubilizing and foaming surfactants can cause bubble burst
Some low molecular weight substances that can be fully mixed with the solution can solubilize the surfactant and reduce its effective concentration. Low molecular substances such as octanol, ethanol, propanol and other alcohols with the function of such dispersant can not only reduce the surfactant concentration in the surface layer, but also dissolve into the surfactant adsorption layer, reducing the compactness of surfactant molecules, thus weakening the stability of foam.
6. Electrolytes disintegrate the double layer of surfactants, leading to the bursting of bubbles
For the surfactant double electric layer interaction with foam to produce a stable foaming solution, the double electric layer of the surfactant can be disintegrated by adding ordinary electrolyte to defoamer.
