Phase Equilibrium and Morphology of High-Molecular Condensation Structures in Three- and Four-Component Systems

Abstract

Using the method of diffusion enrichment with a nonsolvent of polymer solutions in mixed solvents, porous structures are obtained and their structural characteristics are determined. Quasi-binary state diagrams of two four-component systems were obtained. Viscosities of polymer solutions in mixed solvents were measured. The dependences of the reduced viscosity on the polymer concentration are obtained. The slopes ratio and the characteristic viscosities are determined. It is shown that the properties of structural elements ([η] and tgα) of solutions differ significantly depending on the composition of the mixed solvent, and that the positions of the regions of heterogeneity in the quasi-binary phase diagrams for the systems under study correspond to these differences. It is shown that significant differences in the sizes of pores and their proportions in the area of ​​the flat section of the structure correspond to the differences in the constitutional diagrams and the degree of nonequilibrium of the structures, which was qualitatively estimated from the value of [η]. The results indicate that the performed viscometric measurements provide useful information in studying the modification of the morphology of condensation structures by changing the composition of the mixed solvent.