PHYSICO-CHEMICAL PROPERTIES OF AQUEOUS SOLUTIONS OF POLYMER SURFACTANTS

Abstract

Abstract. The rapid progress of water-dispersion paint and varnish materials from the group of waterborne is due to a number of their advantages in comparison with other paint and varnish materials from the category of environmentally friendly. They provide the possibility of low-temperature drying up to room temperature. The purpose is to establish the electrical conductivity and degree of dissociation of surfactants (surfactants) PAN and PES. The methodology of the work included the determination of the specific electrical conductivity (χ, mSm/cm) and the hydrogen index (pH) in freshly prepared and seasoned (at least 48 h) solutions with different additive contents (C = 0÷4 g/dm³) at T = 298 K. Introduction. It was found that at comparable concentrations in water (from 0.25 to 4 g/dm³), PAN is characterized by a greater range of changes in specific electrical conductivity (from 6.21 to 16.97 mSm) than PES (from 3.48 to 4.11 mSm). According to experimental data, sodium polyacrylate is a polyelectrolyte dissociating in water to form polyacrylate macroanions. The degree of dissociation of PAN in dilute solutions (0.25 g / dm³) is maximum and is 28 %. An increase in concentration (From 0.25 g/dm³) is accompanied by a decrease in α to the level of 8 % at S_PAN = 4 g/dm³. Polyethersiloxane copolymer, in turn, is a weaker electrolyte than PAN. The degree of dissociation of its macromolecules in dilute solution (0.25 g/dm³) is 1.5 times less and is 19%). In the region of elevated concentrations (С_PES = 4 g/dm³), α does not exceed 2 %, that is, 4 times lower than in the isoconcentration solution of PAN. Dissociation of amphiphilic compounds is accompanied by the release of slightly acidic functional groups, which provides a shift in the hydrogen index. With respect to bidistilled water (pH = 5.4), pH gradually decreases to a minimum level of 4.26 in PAN solutions and 4.64 in PES solutions. As the duration of the exposure of the solution increases, the change in α and pH is due to the accumulation of hydrolysis products, after 48 hours in the isoconcentration solutions of PAN and PES, the values of the hydrogen index changed by 0.1-0.8 and 0.1-0.4, respectively.