Do you know the aqueous binder thickener?
Aqueous binder thickener is a hydrophobic base modified alkali-swelling associative thickener. It can be used as a thickener or co-thickener for waterborne coatings. At relatively low dosages, waterborne binder thickeners can be effective in shear viscosity.
The colloidal dispersion system stabilized by steric hindrance is very sensitive to temperature changes, especially near the critical flocculation point. For many systems, it may be sensitive over a wide range of concentrations. This flocculation process is usually reversible, and both heating and cooling can occur. Whether msds pe wax flocculation can occur depends on the sign of the Gibbs free energy (AGr) of the flocculation.
AGi=A Hi-TASi(2-22)Napper et al. used Gibbs free energy to analyze the thermodynamic factors leading to flocculation. When AG>0, the dispersion system is stable. When AGi<0, the dispersion will flocculate. In order to ensure the stability of the dispersion system, the following three methods can be used to adjust △Gr to a positive value.
① When AH;>0,AS;>0, it is obvious that the increase in enthalpy is beneficial to the stability of the system, and the increase in entropy is beneficial to flocculation, therefore, this is an enthalpy-stable system.
② When A II K 0, ASr<0, the increase in enthalpy is disadvantageous, and the increase in entropy is conducive to stability, which is called entropy stability.
③When AH 0, AS i<0, AGi>0, flocculation will definitely not occur, which is called an entropy-enthalpy co-stable system.
Experiments have shown that in aqueous dispersion systems, enthalpy stability is more common, while in non-aqueous dispersion systems, entropy stability is common -R-.
In summary, the forces between two particles with an adsorption layer are as follows: first, Van der Waals’s gravitational force VA<0; then, the volume-limited entropy repulsion force Gv>0; the osmotic pressure or desolvation effect GM is 0 ; The adsorption crosslinking energy of the adsorption chain Gaa<0; There is also the electrostatic effect Ga>0 mentioned earlier. The energy Gy that disperses the particles is positive, and the GM of the polymer adsorption layer in a good solvent is also positive. Only Gm is a negative value, which can be ignored. As long as the thickness of the adsorption layer is increased to make the particles reach the saturation coverage, the stability of the dispersion system can be basically guaranteed.
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