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Sorption isotherms for organic-inorganic sorbents used to calculate the free
energy by mixing the components DyUK-T and the construction of its
concentration dependence. It is shown that all systems are characterized by
positive values of free energy of formation. That is, a mixture of hydrophilic
polymer-amorphous silica can be regarded as thermodynamically unstable.
Based on these results and data structure - morphological studies of the
structure proposed scheme organo-inorganic sorbents example systems
amorphous silica - GSH11 and amorphous silica - PVA and distributing it
adsorbed water molecules.
According to the study of the rheological characteristics of the spectra of
turbidity, changes in optical characteristics during drying and swelling sorption
attempted first to compile information about the boundary curves and apply
them to the concentration field Rozeboma ternary diagrams for the example
system PVP-hell. TMOS-water. Here, line 1 separates the opalescent solutions
or subcritical heterophase fluctuations, from the two-phase region. 2 curve - the
curve of the equilibrium swelling - separates the field with an infinite three
dimensional network structure (III) and the local gel formation (II). The latter
should be regarded as non-equilibrium, because it is in this place all the basic
structural and phase transformations, chemical reactions initiated and solvent
evaporation. The equilibrium nature of the line 2 is confirmed by its reversibility
and reproducibility in adsorption desorption cycles. The position of the boundary
curve 2 in the diagram Rozeboma determined by the nature and molecular-mass
characteristics of the hydrophilic polymer.
Since information about the molecular weight adducts of TMOS and their
associates with macromolecules hydrophilic polymer is absent, an attempt of
modeling the evolution of binodal curves in PVP systems - [+ PVP (B102) n]-
water. The calculations used the equations of the theory of polymer solutions,
Flory-Huggins-Scott.
It is seen that [nBn + (Si02)] represents (Si02) n adsorbed polymer is
distributed among the linear PVP macromolecules involved in the formation of
the gel structure, can form a dispersed system in practically all field
concentration of the ternary system. Bright such effect is observed at high
degrees of polymerization components. Confirmation of these results can serve
as electron microscopy data:
- Studied the structure formation in aqueous solutions of TMOS adducts
and mixtures thereof with hydrophilic polymers established critical gelling time
t*, corresponding to a loss of strength systems. It has been shown that the
introduction of the polymer into the reaction mixture TMOS + Water ad usually
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