Abstract
According to the results of the research, the effect of stabilization of dispersions of titanium dioxide in water-acrylic compositions was established. It was proved that in aqueous-acrylic suspensions at all variations of film-forming agent (from 0 to 5 g/dm3), the maximum of stabilizing activity of the surfactants under study is achieved at CSAS=0.25 g/dm3. The minimum deposition rate of titanium dioxide dispersions at a dosing of 0.25 g/dm3 of sodium polyacrylate was at the level of 0.097 10-3 g/s at any content of film-forming agent (Cff=0.5÷5 g/dm3) in suspensions. At the introduction of the same concentration (CSAS=0.25 g/dm3) of the polyether siloxane copolymer, a decrease in sedimentation rate to 0.053 10-3 g/s in suspensions with a limited acryl content (C≤1 g/dm3) was recorded. At an increase in the concentration of a film-forming agent (C>1 g/dm3) in suspensions, sedimentation stability decreased, which is proved by an increase in the sedimentation rate of TiO2 to 0.110∙10-3 g/s at Cff=5.0 g/dm3. It was found that in aqueous-acrylic suspensions with the film-forming content from 0.5 to 1 g/dm3, the minimum average diameter was 2.64÷3.1 μm CSAS=0.25 g/dm3. Further concentration of acryl (Cff=4÷5 g/dm3) at the same dosage of polyether siloxane copolymer was accompanied by an increase in the average particle size up to 4.30÷4.61 μm. The maximum of wedging activity of sodium polyacrylate (CSAS=0.25 g/dm3) corresponds to the same minimum of the average diameter (2–3 μm).
Highlights
The influence of concentration modes of film-forming agent and surfactant on the sedimentation stability of titanium dioxide suspensions was determined by the weight method, the essence of which was the periodic weighing of the sediment collected on a cup of torsion scales [17]
A logical continuation of this study is to explore the effect of the considered additives on the wettability of titanium dioxide
The effect of stabilization of titanium dioxide dispersions in water-acrylic compositions is an additive magnitude determined by the contribution of a film-forming agent and surfactant
Summary
The implementation of a uniform distribution of pigment particles can be achieved by ensuring the sedimentation stability of the system before polymerization begins. Conditions of uniform distribution of pigment are determined primarily by the colloidal-chemical properties of the system, namely dispersity and polydispersity of pigment particles, the state of its surface, sedimentation and aggregative stability. One of the main methods for purposeful regulation of the properties of polymer composite materials and coatings is the use of surfactants (SAS). In the technology of polymeric paint and varnish materials and coatings, the use of amphiphilic polymer compounds of various chemical compositions is constantly expanding. As a result of adsorption phenomena, their physical (and sometimes chemical) interaction with the surface of dispersed particles and substrates, associations with film-forming molecules, the deformation-strength, insulating, adhesive, coloristic, and other properties of paint and varnish coatings can change significantly
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