Many types of defoamers, organic siloxane, polyether, and an ether-grafted silicone-containing amines, imines and amides, having a defoaming faster suds longer for a wider range of media, Even harsh media environments such as high temperature, acid and alkali characteristics.
Defoamers defoaming mechanism
1. Reduce the surface tension of the bubble led to a partial bubble burst
The mechanism on the origin of the higher alcohols or vegetable spread on the foam, the foam when it is dissolved in the liquid, can significantly reduce the surface tension of the area. Because these materials are generally less water solubility, the surface tension reduction is limited to a partial foam, the foam around the surface tension almost no change. Surface tension reduction of the surrounding portion is strongly pulling extension, and finally burst.
2. Defoamers can damage the membrane elasticity and cause bubbles burst
Defoamer added to the foam system, will spread to the gas-liquid interface, the surface active agent having the ability to recover foam stabilization elastic film hardly occurs.
3. Defoamers film can promote drainage, resulting bubble burst
The discharge rate of the foam stability of the foam can be reflected, adding a substance to accelerate the discharge of foam, can also play a defoaming effect.
4. Add a hydrophobic solid particles can cause bubbles burst
In the bubble surface hydrophobic solid particles attract hydrophobic end of the surfactant, the hydrophobic and hydrophilic particles are produced into the aqueous phase, which play a role in defoaming.
5. Solubilizing co-surfactant may cause foam bubbles to burst
Some fully mixed with a solution of low molecular substances can be co-foam surfactants solubilize their effective concentration. This effect has a low molecular weight substances such as octyl, ethanol, propanol, can not only reduce the surfactant concentration of the surface layer, but also dissolved in the adsorbed layer of surfactant, surfactant molecules reduce the close inter- degree, thus weakening the foam stability.
6. Neutralized surfactant electrolyte electric double layer cause bubbles burst
By the interaction of surfactant foam electric double layer bubble generating liquid stability of the electrolyte can be added to an ordinary electric double layer is neutralized surfactant defoaming effect.