Thickening mechanism

Thickening mechanism of inorganic compounds

The system using inorganic salt as thickener is generally surfactant aqueous solution system, in which surfactant forms micelles. The existence of electrolyte increases the association number of micelles, which leads to the transformation of spherical micelles into rod micelles, thus increasing the motion resistance and viscosity of the system.

However, when the electrolyte is excessive, it will affect the micelle structure, reduce the movement resistance, and thus reduce the viscosity of the system, which is called "salting out". Therefore, the mass fraction of electrolyte is generally 1% ~ 2%, and it works with other thickeners to make the system more stable.

Cellulose thickener

The thickening mechanism of cellulose thickener is that the hydrophobic main chain of cellulose thickener molecules is associated with surrounding water molecules through hydrogen bonds, which increases the fluid volume of polymer itself, reduces the free space of particles, and thus improves the viscosity of the system. The viscosity can also be improved by molecular chain winding, which shows high viscosity at static and low shear, and low viscosity at high shear. This is because the cellulose molecular chain is in disorder at static or low shear rate, which makes the system show high viscosity; However, at high shear rate, the molecules are arranged in an orderly manner parallel to the flow direction, which is easy to slide each other, so the viscosity of the system decreases.

Natural rubber thickener

The thickening mechanism of natural gum thickener is that three hydroxyl groups in polysaccharide interact with water molecules to form a three-dimensional hydration network structure, thus achieving the thickening effect.