Views: 0 Author: Site Editor Publish Time: 2023-08-16 Origin: Site
In the use of pesticides, only a few cases are the direct use of the original drug, and most of the cases are mixed with other additives and solvents to improve its use value and reduce the cost of use. Surfactant is a kind of additives that can give greater play to the value of pesticides and reduce the cost of pesticides. It plays the role of emulsification, foaming/defoaming, dispersion and wetting, and has been widely used in pesticides.
Surfactants can improve the interfacial tension between the components in the emulsion and form a uniform and stable dispersion system. The surfactant structure has both hydrophilic and oil-philic groups, which adsorbed on the oil-water interface, can reduce the interfacial tension and reduce the energy required to form the emulsion, so as to improve the stability of the emulsion.
The effect of emulsified pesticide is better than that of other pesticide formulations when the active ingredient of pesticide is dispersed in water in a small state. Emulsifiers directly affect the stability of pesticide emulsion, and then affect the efficacy.
Different droplet sizes of pesticides have different stability: when the pesticide particles < 0.05μm, in water is solubilized state, more stable; When pesticide particles are 0.05 ~ 1μm, they are basically dissolved in water and remain relatively stable. When the pesticide particles are 1 ~ 10μm, there are some large particles in the water, and after a certain time there will be precipitation or precipitation; When pesticide particles are more than 10μm, they are obviously suspended in water and are extremely unstable.
With the change of pesticide structure, some highly toxic organophosphorus pesticides are gradually replaced by some safe, efficient, low toxic and complex chemical structure pesticide varieties. Some heterocyclic compounds, especially nitrogen-containing pyridine, pyrimidine, pyrazole, thiazole and triazole, are solid and have low solubility in conventional solvents, so new, high-efficiency and low-toxicity emulsifiers are needed to emulsify new pesticides.