Papers by Author: Li Jun Sun

Abstract: In order to study the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes in engineering application, the influences of the organic modifier dosage, oscillation intensity, oscillation time, temperature, pH, sodium salt concentration, calcium salt concentration on the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes were systematically investigated. Research results show that the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes slightly reduces with the increases of oscillation intensity, oscillation time and temperature, but the impact isn’t obvious. The more the organic modifier dosage is, the more unstable the Montmorillonite / Octadecyl trimethyl ammonium complexes are. The stability of the Montmorillonite / Octadecyl trimethyl ammonium complexes decreases significantly under the medium conditions of lower or higher pH. The higher the concentration of sodium salts is, the more stable the Montmorillonite / Octadecyl trimethyl ammonium complexes are, but calcium salts are on the contrary.

Abstract: Thixotropic gel can be formed in the organic solvents is one of the most important application characteristics of montmorillonite/octadecyl trimethy ammonium chloride complexes. The key factor influencing the formation of gel is the preparation technology, and the posterior disposal process is also an important affecting factor which should be paid more attention to. In the paper, the effects of washing, drying temperature, grind size, activators and the polarity of solvents on the gel viscosity of montmorillonite/octadecyl trimethy ammonium chloride complexes were systematically studied. The research shows that fully washing can elute the octadecyl trimethy ammonium chloride ions or molecula adsorbed on the layer and the edge of montmorillonite crystal, and improve viscosity of gel formed by the complexes. Controlling the drying temperature at the range of 90－100°C and ensuring the complexes with a little interlayer water are favorable for the gel formation of the complexes. When the granularity of the complexes is less than 0.074mm, particles in solvents can fully produce solvation action, solvent swells and strips, and then form the thixotropic organic gel. Using the 95% ethanol as the activator, when its dosage is 5 wt%, its activation effect is better. The stronger the polarity of the dispersing solvent is, the more favorable the formation of the organic gel with higher viscosity is.