Application of defoaming agents in daily life
Any factor that can destroy the stability of foam can be used for defoaming. Defoaming covers two factors: “foam suppression” and “foam breaking”. Silicone defoamers have this function. They can reduce the surface tension of water, solutions, suspensions, etc., prevent the formation of foam, or reduce the original foam, and usually have a selective effect. Generally, physical defoaming methods are difficult to defoam instantly, while chemical interface defoaming is very fast, convenient and efficient. In short, defoamers refer to agents with chemical and interface chemical defoaming effects. The process of “foam suppression” and “foam breaking” of defoamers is: when the defoamer is added to the system, its molecules are randomly distributed on the surface of the liquid, inhibiting the formation of an elastic film, that is, terminating the generation of foam. When a large amount of foam is generated in the system, the defoamer is added, and its molecules are immediately spread on the surface of the foam, spreading rapidly to form a very thin double film layer, which further diffuses, penetrates, and invades in layers, thereby replacing the original foam film wall. Due to its low surface tension, it flows to the liquid with high surface tension that produces foam. In this way, the defoamer molecules with low surface tension continue to diffuse and penetrate between the gas-liquid interface, making its membrane wall thinner rapidly. At the same time, the foam is strongly pulled by the surrounding membrane layer with high surface tension, which causes the stress around the foam to be unbalanced, resulting in its “bubble breaking”. The defoamer molecules that are insoluble in the system re-enter the surface of another foam membrane, and so on, and all the foams are destroyed. After breakfast, have a cup of coffee to refresh yourself. Drinking instant coffee is a habit of many people, but do you know what is in instant coffee? The answer you want is on the back of the instant coffee packaging bag: “white sugar, non-dairy creamer, glucose syrup, edible hydrogenated vegetable oil, stabilizer, sodium caseinate (containing milk protein), emulsifier, edible flavoring/flavoring agent and anti-caking agent.” There are many food additives around us. In his book “The Truth of Food Revealed”, Abe Tsukasa, the “God of Food Additives” in Japan, revealed that the average person eats about 10 grams of additives every day, which is about 4 kilograms a year. Why use additives? Food additives are natural substances or synthetic chemicals added to food, which can make food last longer, taste better, or be more convenient to make and cost less. As far as the additives themselves are concerned, additives from natural substances are much less harmful than chemically synthesized additives, but the former are expensive, usually several times or even dozens of times the latter. Food additives are widely used, and no country has banned the use of food additives. In the United States, one of the most widely used countries, more than 2,000 types are allowed. In the 1970s, there were only dozens of food additives approved for use in my country, and now there are nearly 2,000 types of 223 categories, including preservatives, coagulants, quality improvers, flavor enhancers, and nutritional enhancers. GB2760-2007, which was officially implemented on June 1 this year, clearly stipulates the dosage and scope of use of most food additives.
