is a kind of surfactant composed of polydimethylsiloxane as its hydrophobic main chain and connecting one or more silicone polar groups at the intermediate or end position. According to the chemical properties of hydrophilic group R in its chemical structure, silicone surfactants can be divided into four categories: anionic, cationic, non-ionic and zwitterionic. Among them, non-ionic surfactants are the most studied and widely used. Next, XinJiaYi will show you the classification of silicone surfactants:
1. Cationic silicone surfactant
If R group contains structural units such as alkyl quaternary ammonium compound, amide quaternary ammonium compound and imidazoline derivative quaternary ammonium compound, it is called cationic silicone surfactant. Among the cationic silicone surfactants, cationic polysiloxane quaternary ammonium salt surfactants are the most widely used. Cationic polysiloxane quaternary ammonium salt surfactant has large molar mass, can be compatible with anionic surfactant, has no irritation to human skin and eyes, has certain antibacterial ability, does not produce free ammonium in alkali solution, and has stable properties. The macromolecules of the product contain hydrophobic long-chain polysiloxane chains, which makes it have excellent smoothness and softness.
2. Anionic silicone surfactant
When the R group contains structural units such as phosphate salt, sulfate, carboxylate, sulfonate and sulfosuccinamide ester, it is called anionic silicone surfactant. When R is the following structure, it is called anionic polysiloxane phosphate surfactant.
When R 'is a fatty acid functional group, it is a polysiloxane phosphate betaine amphoteric surfactant. The surfactant molecule not only has the structure and properties of phosphate betaine, but also has the structure and properties of polysiloxane. If low molar mass polysilane is selected, polysiloxane has weak properties; On the contrary, if polysiloxane with large molar mass is selected, the characteristics of polysiloxane are remarkable. These products have the characteristics of low toxicity, antibacterial, hard water resistance and good compatibility with various surfactants.
3. Nonionic silicone surfactant
When R group contains polyether, alkanolamide, ester, glycoside and other units, it is a non-ionic surfactant. Among them, polyether silicone surfactant is the most widely used.
Nonionic polyether silicone surfactant is composed of polysiloxane segment (a) and polyether segment (b). Its combination modes include AB type, ABA type, bab type, (AB) n type, branched chain type and side chain type. There are two ways to connect polyether segments and siloxane segments, namely Si-O-C type and Si-C type. The former is unstable and belongs to hydrolytic type; The latter is stable to water and is called non hydrolytic.
4. Amphoteric silicone surfactant
If R group contains phosphate betaine or betaine and other structures, it is called amphoteric polysiloxane surfactant.