Mechanism of Silicone Defoamer


The defoaming or anti-foaming ability of organosilicon is due to its low surface tension. Silicone compounds (silicone oil) interfere with the surface tension of the gas-liquid boundary, resulting in defoaming effect.


The functions of defoamers are also defined according to the three mechanisms of defoaming, defoaming and anti-foaming.


Bubble breaking: when it enters the bubble from the air side relative to the foam, it will burst together.


Bubble suppression: from the liquid side into the bubble, the bubble will be destroyed.


Debubbling: Invade bubbles from the interface of bubbles, so that bubbles come together and float out of the liquid surface.






Types of organosilicon defoamers


1. Water Emulsion Defoamer


With polydimethylsiloxane (dimethylsiloxane) as the main body and silica complex, O/W water emulsion defoaming with different concentration (suitable for water medium defoaming occasion) or high concentration silicone paste were prepared under the action of surfactant (emulsifier). When used, it was used by smearing method or temporary dilution.


2. Defoamer for Oil System


Silicone oil is carried by solvents and dispersed into the shooting fluid. Solvent diffusion, silicone oil or droplets play a defoaming role (generally high and low viscosity silicone oil blending) or make silicone oil/mineral oil dispersion. The petroleum industry needs a large number of organosilicon surfactants as demulsifiers.


3. Solid Powder Defoamer


Powdery solid carrier with 2%~5% organosilicon defoaming component and 98%~50% mass fraction.


4. Antifoam rod


Preparation of silicone oil, sodium sulfonate and wax.


5. Self-emulsifying and self-dispersing defoamer


The introduction of hydrophilic group (polyether modified silicone oil) into polysiloxane molecular chain by Polysiloxane and polyether copolymerized organosilicon surfactant can significantly improve the dispersion of organosilicon in water or become self-emulsifying, and become a kind of special defoaming agent, which defoams above cloud point and is suitable for high temperature and high pressure jet dyeing and other defoaming.


Conversion from organosilicon