Wetting agent must not only have the external condition of low surface tension, but also the internal condition that its own molecular structure has excellent affinity for certain inorganic or organic substances, and the reduction of surface tension alone is not enough to produce wetting of substances.
The defoaming mechanism of chemical substances
The defoaming method suitable for coatings is to use defoaming agents. Any substance that can quickly disappear by adding a small amount of substance is called a defoamer. Most defoamers belong to the surfactant type. Defoamer is a substance that can produce stable surface tension imbalance in the foam system and break the surface viscosity and surface elasticity of the foam system. It should have low surface tension and HLB value, have a lower density than the foaming medium, and be insoluble in the foaming medium (suitable incompatibility).
It is very easy to uniformly disperse in the foam medium according to a certain particle size, cas number polyethylene wax and produce continuous and balanced defoaming ability. When the foaming medium is to foam for some reason, it can first prevent the generation of foam. In the foam system that has already formed foam, it can spread quickly, destroy the elastic membrane of the bubble, and make it burst.
American colloidal chemist Ross conducted experiments and observations on foaming systems with various surfactants, and found the correspondence between the solubility of defoamers in the foaming liquid and the defoaming effectiveness, and put forward a hypothesis: In the solution, the dissolved solute is the foam stabilizer; the insoluble solute is the defoamer when the penetration coefficient and the dispersion coefficient are both greater than zero [20.21].
Leave a message
We’ll get back to you soon