Foam can be a major issue in some industries and products to overcome this are used across the wide spectrum of different markets ranging from paper pulp processing, paints and water treatment to name a few. Surfactants that generate foam are added to a wide range of applications for various reasons but in some applications, foam generation can cause issues. Also in some application such as sugar beet and pulp processing, foam is generated naturally during processing. The addition of an additive to suppress the generation of foam levels is therefore required, and such foam control agents are known as either antifoams or defoamers.
Both antifoam or defoamer is the same in many respects but the term antifoam suggests the prevention of foam and a defoamer operates by causing the collapse of the foam that has already been generated.
How an antifoam works
Antifoams operate by the migration toward the air–water interface. The antifoam then substitutes the surfactant at the surface which then prevents the foaming agents from interaction with air to form foam.
The following depicts how an antifoam prevents foam generation at the air-water interface.
How a defoamer works
A defoamer operates by the breakdown of foam that has already been generated. The following schematic illustrates how they work
There are a number of foam control products in the marketplace. The most common types are either silicon based or mineral oil types.
Mineral oil type
Lankem have developed two types based on a mixture of mineral oils, complex esters and hydrophobic particles. In some applications, the use of silicone oil can cause major problems due to the substantive nature of silicone, which can have a detrimental effect. In these application, such as costings mineral oil based defoamers are the preferred option
For low to medium foam
Such as emulsion polymerisation, coatings and applications of medium to low agitation
We recommend the use of Dfoam AX1... more details
For high foam
For application where foam is a major issue such as applications of high and continuous agitation.
We recommend the use of Dfoam AR2... more details
Silicone oil types
Polydimethylsiloxane PDMS (INCI name: Dimethicone is the simplest and most widely used form of silicone that is used in defoamer systems. The oil is emulsified in water to produce a very effective defoamer.
For more details please view the blog.