The Choice of Filler in the Formulation of Sol-Silicate Paints

It is proposed to apply thermodynamic criteria when choosing a filler in paint formulations - critical surface tension, Hamaker constant. The values of the critical surface tension of a liquid (ethanol solutions with different water content) at the interface with a solid (different fillers) are calculated. The energy of interaction between the filler particles was estimated by the value of the Hamaker constant. Determined that microcalcite has a higher critical surface tension, compared to other fillers. It is shown that when calcite is used as a filler, the inter particle interaction is enhanced. It was found that the use in sol silicate paints as a filler of calcite contributes to obtaining a higher cohesive strength of coatings due to an increase in the contribution of dispersion forces. Based on the study, the numerical values of the Hamaker constant and the critical value of the surface tension of various fillers were obtained. It allowed makes it possible to choose the optimal type of filler. It has been established that there is a linear relationship between the value of the interaction energy between the filler particles (Hamaker constant) and the tensile strength of the coatings. A mathematical model of cohesive strength is obtained depending on the value of the Hamaker constant.