A defoamer, also known as an anti-foaming agent or foam inhibitor, is a chemical substance that lowers the surface tension of a liquid and destroys air bubbles and foam in the liquid. Defoamers are usually used in various industries and production processes, such as chemical, pharmaceutical, paint, food and other fields. Its main function is to prevent the accumulation of air bubbles and foam on the surface of the liquid, and reduce the influence of the surface tension of the liquid on the production process.
The following are some properties that may need to be tested for defoamers, as detailed in the table below:
| performance | Detection method |
|---|---|
| Defoaming properties | Observe foam stability and defoaming speed |
| Dispersion properties | Determination of Dispersion Time and Degree of Dispersion |
| Solubility | Determination of Solubility of Defoamers at Different Temperatures |
| Surfactant energy | Determination of the effect of defoamers on the surface tension of water |
| stability | Determination of the stability of defoamers at different temperatures, pH values and water hardness |
| Durability | Determination of performance changes of defoamers after long-term use and storage |
| chemical composition | Determination of the chemical composition of defoamers using chromatography, infrared spectroscopy, etc. |
| Environmental protection | Determination of environmental performance such as toxicity and biodegradability of defoamers |
NBCHAO reminds you: the specific properties that need to be tested should be determined according to the field of use and application requirements of the defoamer.
Detection method
Defoaming properties
Defoaming performance is usually evaluated by observing the stability of the foam and the speed of defoaming. During the specific operation, add a certain amount of defoamer to a certain amount of liquid, and then observe the stability and defoaming speed of the foam within a certain period of time. The faster the defoaming speed and the more unstable the foam, the better the defoaming performance of the defoamer.
Dispersion properties
Centrifugation, filtration and other methods can be used to measure the dispersion performance of the defoamer. The centrifugation method is to add the defoamer to the water, and then use a centrifuge to centrifuge the mixed liquid. According to the relative density of the liquid, the liquid is divided into different layers, and the dispersion performance of the defoamer is evaluated according to the distribution of the defoamer in different layers. . The filtration method is to add the defoamer to water, then use a filter to filter, and evaluate the dispersion performance of the defoamer according to the filtration speed and filter residue.
Solubility
The solubility of the defoamer can be evaluated by adding a certain amount of defoamer to a certain amount of solvent at different temperatures, then shaking or stirring for a certain period of time, and measuring the weight or concentration of the remaining undissolved defoamer to evaluate its solubility.
Surfactant energy
The usual way to evaluate the effect of a defoamer on the surface tension of water is to measure the degree of surface tension reduction. Surface tension can be measured by dynamic and static methods, dynamic methods are usually measured using interfacial tensiometers or ring methods, static methods using equilibrium methods or bubble pressure methods.
stability
The stability test is by testing the stability of the defoamer under different environmental conditions. For example, the stability of defoamers can be tested under different conditions such as temperature, pH value and water hardness. The stability test can be evaluated by observing the appearance, measuring the pH value, viscosity, surface tension and other indicators.
Durability
The durability test can be evaluated by measuring the performance change of the defoamer after long-term use or storage. For example, the defoaming performance, surface tension, pH value and other indicators of the defoamer can be measured at different time periods or at different temperatures to evaluate its durability.
toxicity
The detection of defoamer toxicity usually includes acute toxicity and chronic toxicity. Acute toxicity test can be carried out by means of animal experiments or cell culture to evaluate the acute toxicity of defoamers to organisms. Chronic toxicity tests usually require long-term exposure or long-term drinking to evaluate the chronic toxicity of defoamers to organisms.
other properties
In addition to the above properties, defoamers may also need to test other properties, such as antistatic properties, high temperature resistance, etc. The detection method can be selected according to specific requirements, such as using an electrometer or a high-temperature constant temperature bath for measurement.
In short, to detect the performance of defoamers, it is necessary to select the corresponding test method according to the specific performance. The selection of detection methods and the control of experimental conditions are self-evident for the accuracy and repeatability of test results.
