Defoamer
**Defoamer Properties**:
– Defoamer is insoluble in the foaming medium and has surface active properties.
– It has low viscosity and spreads rapidly on foamy surfaces.
– Defoamer destabilizes foam lamellas on air-liquid surfaces.
– It causes rupture of air bubbles and breakdown of surface foam.
– Entrained air bubbles are agglomerated, and larger bubbles rise quickly to the liquid surface.
**History of Defoamers**:
– Early defoamers used kerosene, fuel oil, and vegetable oils.
– Fatty alcohols were effective but expensive antifoams.
– Silicone-based defoamers were experimented with in the 1950s.
– Hydrophobic particles in light oil were patented in 1963.
– Water-based and water-extended defoamers emerged due to the oil crisis in 1973.
**Classification of Defoamers**:
– Oil-based defoamers: Have an oil carrier, such as mineral or vegetable oil, and are best at reducing surface foam.
– Powder defoamers: Are oil-based defoamers on a particulate carrier like silica, used in powdered products to reduce foam.
– Water-based defoamers: Contain oils and waxes dispersed in a water base, best at releasing entrained air.
– Silicone-based defoamers: Are polymers with silicon backbones, good at reducing surface foam and releasing entrained air.
– Alkyl polyacrylates: Suitable for use as defoamers in non-aqueous systems, focusing on air release rather than surface foam breakdown.
**Industrial Problems and Applications**:
– Industrial problems caused by foam include liquid level issues, process speed reduction, and equipment availability.
– Testing defoamers can be done by observing surface foam, testing entrained air, and drainage time through a filter.
– Applications of defoamers include detergents, food preparation, industrial processes, and more.
**Foam and Foaming Agents**:
– Foam is a substance formed by trapping pockets of gas in a liquid or solid.
– Foaming agents help produce foam in various industries.
– Understanding the chemistry of foams is crucial for controlling their formation.
– References for further reading on foams and foam control are provided.
– The importance of defoamers and antifoams in different industries is highlighted.https://en.wikipedia.org/wiki/Defoamer