Say Goodbye to Foam
The most productive antifoams have traditionally been synergistic mixtures of hydrophobic liquids and solids. Examples include “non-polar oils”, like minerals, silicones; ”polar oils” such as fatty alcohols, fatty acids, alkyl amines; “hydrophobic solids” treated silica, aluminum oxide, polypropylene. These compounds almost always contain additional surfactants to enhance other properties required in the finished blend i.e., surface wetting, emulsification, particle dispersion, or detergency. One of the confusing aspects of Vertethe’s surfactant application is that the chemical compound that has antifoaming properties in one application might be used as an emulsion breaker in another.
In many ways, the art of breaking or preventing foam is as complex as its formation. Certainly, it is a subject that has and is currently undergoing intense study. There are no hard and fast rules governing the efficacy of a given antifoam formulation in any application. For the most part, each application is based on empirical data, usually bench-level trials. There are, however, some physical and chemical factors consistent among observations made while studying antifoams and their functionality under different conditions. Factors that affect antifoam performance include:
Solubility: Most antifoams exhibit extremely low solubility in aqueous solutions.
Droplet Size: The entry force required to allow the antifoam droplet to enter the bubble wall generally increases as antifoam droplets become smaller.
Presence of Hydrophobic Solids: Liquid/solid mixtures are usually more effective than components used alone.
Environmental Shear: This is principally due to solid/ liquid separation, and antifoam droplets being too small to bridge the bubble lamellae.
Repeated Exposure of Foaming: Often repeated exposure of foaming eventually exhausts the antifoam’s ability to inhibit formation. This is probably due to the separation of hydrophobic solids and reduced droplet size. Multiple shake test experiments have shown that some antifoams gradually lose their antifoaming ability.
Surfactant Concentration: Higher surfactant concentrations tend to reduce antifoam effectiveness by increasing the entry force necessary to bridge the interfacial film.
Dissolved Salt Species: The presence of high valence metal ions reduces antifoam effectiveness. Counterions surround the polar ends of the surfactant molecules, reducing their electrostatic interaction with other surfactant molecules in the film.
To understand the antifoaming mechanism, a basic understanding of foam is necessary. Foam bubbles are liquid polyhedral cells encapsulating a gas. The Lamellae are the faces separating two cells. The Plateau Border is the thicker junction between lamellae. Vertexes are the junctions of four Plateau Borders.
Emulsified droplets of insoluble oil suspended in a solution enter the lamella formed by surfactant films as a gas bubble displaced above the bulk surface. The force required for the droplet to be incorporated into the film is known as the entry barrier. Our R&D studies have shown that the suspended hydrophobic solids in the antifoams reduce the droplet entry barrier into the film thereby making them more efficient.
The foam structure begins to drain immediately after forming causing the lamella to thin. The incorporated antifoam droplet bridges across the film creating an oil lens. The droplet is stretched as the film contracts and eventually ruptures breaking the bubble. This action takes place in only a few seconds and is characteristic of our product range: fast - antifoams.
As you know, the best solutions come from the best know-how. Our range of industrial antifoams, antifoams agents, powder antifoams, industrial defoamer, defoamer emulsion, flowing emulsion, etc., are widely used for various applications such as liquid fertilizer industry, paint, pulp and paper, industrial cleaning, food processing systems, wastewater treatment, agrochemicals, inks, dyes, textiles, and others.
Our MAXANT Antifoam products have been appreciated for their good dilution stability and good foam decreasing performance. We always take into consideration market conditions and the necessity of supplying products to our customers in the most economical conditions. Our well-educated technical service teams are closely supervising applications with our customers and solve their problems immediately with on-site technical support. And the best point is, we are really enjoying the work we do. Meanwhile, please forget your problems with foam because we have the solution.