Rheological properties and concentration cross-overs of anionic acrylamide copolymers in saline solutions (potassium chloride) were investigated by using capillary viscometer method. Area of non-overlapping coils between the crossover concentration and the concentration of fluctuation mesh formation was determined; it was shown that with increase of salt concentration this area practically disappears, i.e. mass transfer mechanism changes near the crossover concentration. It was shown that at low concentrations of potassium chloride increasing the content of ionic groups of macromolecules leads to reduction in the crossover concentration and increase in the effective volume. It is found that the kaolin adsorption capacity decreases when polymers are adsorbed from saline solution, and the adsorption constant is significantly higher in the presence of salt than in water.

The effect of sodium dodecyl sulfate and sodium oleate on the structural-rheological properties of a dispersed hydrogel based on polyacrylic acid was studied. It was shown that the viscosity of hydrogel compositions with surfactants is higher than the viscosity of the individual components and increases with increasing temperature from 20 to 40 °C. Compositions with sodium oleate are non-Newton liquids and exhibit thixotropic properties.

A cationic flocculant with an amide-type polymer matrix was synthesized by modifying polyacrylamide according to the Mannich reaction. The use of a modified polymer leads to an increase in the adsorption of the polymer on solid phase particles in an aqueous dispersion of kaolin, an increase in the rate of kaolin sedimentation by a factor of 1.2–1.4, and makes it possible to expand the concentration range of dispersion destabilization compared to polyacrylamide.

Аннотация. Показано, что устойчивость водной и солевой дисперсии каолина уменьшается при введении катионного полиэлектролита и его смесей с поверхностно-активным веществом. Флокулирующая способность катионного полиэлектролита уменьшается с ростом содержания ионогенных групп. Установлено увеличение флокуляции в солевой среде при введении смеси полиэлектролита с анионным ПАВ, а также при последовательном добавлении компонентов в дисперсию каолина. Ключевые слова: дисперсные системы, полиэлектролит, флокуляция, поверхностно-активные вещества, агрегативная устойчивость Для цитирования. Влияние полиэлектролитов и поверхностно-активных веществ на устойчивость микрогетерогенных систем / П. Д. Воробьев [и др.] // Вес. Нац. акад. навук Беларусi.

The features of clay-saline (potassium and sodium chlorides) dispersions flocculation using polyacrylamide and its cationic and anionic copolymers are described, including the effect of flocculant concentration, solid concentration in dispersion, method of polymer dissolution in water or saline solution on the sedimentation rate and flocculation density. It is shown that polyacrylamide has the highest flocculating ability towards clay-saline dispersion, and cationic copolymers – the lowest effect. It is shown that in concentrated clay dispersions flocculation starts at lower flocculant dose rate and occurs in a narrow range of polymer concentrations. The sedimentation rate of clay in salt dispersion increases by 15–20% with the introduction of flocculant in two stages, and by 50% times – with consequent dosing of cationic and anionic flocculant. It is also stated that polymer solutions prepared using concentrated salt solutions of potassium and sodium chlorides provide a higher efficiency of clay flocculation in comparison with solutions of polymers prepared in water.