Mechanism of Anti-foaming agent

In order to learn how the anti-foaming agents play a role in the foaming medium, and how to

use anti-foaming agents more rationally and effectively, we must be familiar with its mechanism and general properties.

When the foaming system foams violently, the foam will disappear immediately after adding antifoam agents. In fact, the role of anti-foaming agent is to counteract the foam stabilizing effect of the foam-promoting substance. Foam is inherently very unstable, if pure water is stirred, foam will also form, but once the stirring is stopped, the foam will disappear immediately. If a foam-promoting substance is added to the water, it is difficult to burst the foam due to its stabilizing effect. So even if it is a pure surfactant that foams, it will not form a stable foam because there is no foaming aid. The defoaming mechanism of anti-foaming agents is introduced below.

 Defoaming mechanism related to foam stabilizing factors

 With the continuous understanding of the foam stabilization factor, people's understanding of the defoaming mechanism is also deepening. Foam stabilization factors are diverse, and the defoaming mechanism is also diverse.

It can reduce the local surface tension of the foam and cause the bubble to burst.

When the anti-foaming agent adheres to the bubble film, it is immersed in the bubble film liquid, which will significantly reduce the surface tension there. Because in the water system, the solubility of the active ingredients of the anti-foaming agent to water is small, the reduction of the surface tension is limited to the part of the bubble film, and the surface tension around the bubble film hardly changes. The part with reduced surface tension is intensively pulled and stretched around, and finally causes the bubble to burst.

2) The anti-foaming agent can destroy the elasticity of the film and cause the bubble to burst

   As the surface of the bubble film adsorbs surfactant, the surface tension is reduced. Therefore, when the bubble film is locally thinned by local pressure, the surface tension will increase due to the thinning of the surfactant. It is precisely because of the difference in surface tension between the new surface and the original surface that when the bubble film is thinned by the external impact, an elastic restoring force is generated, and the bubble film can not be broken and played a role in stabilizing the bubble. If we manage to destroy this elasticity, we can destroy the stability of the foam. Some experts believe that the role of anti-foaming agent is to destroy the elasticity of the bubble film. When the anti-foaming agent is added to the foam system, it will diffuse to the gas-liquid interface, making it difficult for the foam-stabilizing surfactant to recover the elasticity of the film.

Amber Zhang Ms.

Foreign trade 

Zhejiang Ruico Advanced Materials Co., Ltd. (Stock No.873233)

Add: No.188, Liangshan Road, Linghu Town, Nanxun District, Huzhou City, Zhejiang Province, China 313018

Phone: +86 (572) 2903236

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Website: www.ruicoglobal.com 

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