Research on the application of cationic surfactants in industrial cleaning
In industrial cleaning, compounding the appropriate (structure, quantity) of cationic surfactants will significantly increase the efficiency of cleaning oil. In the structure of the general selection of hydrophobic chain activity is not strong cationic surfactants, this is because the higher the surface activity of the cationic hydrophobic chain, the more likely to be adsorbed on the solid surface, making the surface hydrophobic, oleophilic, easy to adsorption of oil, resulting in the redeposition of dirt. At the same time, it will form insoluble substances with anionic surfactants in the detergent system or anionic substances such as fatty acid soaps in the oil, which will be deposited on the solid surface and form a more difficult to remove the scale. Modification of the hydrophobic chain of the cationic surfactant makes it less hydrophobic and greatly enhances its compounding and decontamination performance.
Cationic surfactants with special structure
Short chain, branched structure
Alkoxylated quaternary ammonium salt cationic surfactants
Sugar quaternary cationic surfactants
Sugar ester quats
Polyhydroxy polyquaternary ammonium salts
Gemmich quaternary ammonium salt cationic surfactants containing heteroatoms
The solubilization performance of cationic surfactants is second only to nonionic surfactants, higher than amphoteric and anionic surfactants, and the interfacial adsorption performance is strong, but due to the ease of adsorption on the surface of negatively charged solids, which makes the surface of the solids hydrophobic and can not be wetted, and makes it limited in the cleaning application, which has long been neglected in the cleaning field. In the anionic surfactant system, the addition of a small amount of cationic surfactants, so that the surface adsorption layer of the intermolecular electrostatic repulsion weakened, the adsorption layer is arranged more tightly, the surface activity of the system will be significantly enhanced, and the performance of decontamination has been improved.
In the nonionic surfactant system, the addition of cations enhances the adsorption of the system on the solid surface, and the decontamination speed is significantly improved. However, the compounding performance of conventional cationic surfactants is poor due to structural limitations. Through the modification of its hydrophobic chain, so that the activity of the hydrophobic chain is reduced, can make it not only maintain the advantage of cation adsorption on the solid surface, but also has little effect on the system’s wettability, which greatly improves the performance of its compounding with anionic and nonionic surfactants, as well as its decontamination performance. It provides a more efficient choice for the cleaning system. Therefore, the design and development of cationic surfactants with different hydrophobic chain structures and their flexible application in industrial cleaning agents will become one of the focuses of future research and development of surfactants and industrial cleaning industry, and the prospects are very broad.
There are the following elements in the design, development and application:
(1) In the structure of surfactants, pay attention to the balance of hydrophilic and hydrophobic groups to ensure surface activity.
(2) The development and application of baryon quaternary ammonium surfactants should be a perfect combination of the good detergency of ethoxylated, sugar-based and other structures of surfactants and the high adsorption of quaternary ammonium surfactants as well as the high efficiency of baryon surfactants.
(3) The application of special structure cationic surfactants can enhance the detergent’s oil removal efficiency (fast oil removal) and capacity (long service life), and can also realize oil stripping (i.e., after the oil is separated from the surface, it is suspended in the cleaning solution, and the oil and water are separated quickly after standing). Some special structure of the cationic surfactant, hydrophobic chain with the decontamination of non-ionic surfactant performance is more prominent, for some specific oil contamination, under certain cleaning conditions, the use of such cationic surfactants alone (without adding other surfactants) formulated cleaning agent, can also achieve good decontamination results.
(4) The more similar the hydrophobic chain of the surfactant is to the carbon chain structure of the oil, the stronger the decontamination effect. On the other hand, cationic surfactants need a suitable structure, ratio, to ensure compatibility with other surfactants in the system and the oil in the fatty acid soap and other surface-active anionic substances.
(5) Ionic surfactant foam is more stable than non-ionic surfactant foam, performance is affected by electrolyte, the application needs to be based on the conditions of use, control system foam, pay attention to the electrolyte additives in the system, hard water and dirt and other charged particles such as metal ions on the performance of its impact.
