Thermodynamics of solvation and association in solutions of fluorosiloxane rubber and polychloroprene in organic liquids

Abstract

The enthalpy of dissolution and concentration dependences of the enthalpy of dilution of solutions of fluorosiloxane rubber and polychloroprene in different organic liquids are determined by means of isothermal microcalorimetry. It is established that the processes of polychloroprene dissolution are accompanied by exothermic effects, while those of fluorosiloxane rubber are accompanied by endothermic effects. The calorimetric data are analyzed using the UNIQUAC model to calculate the model parameters associated with the local concentrations of components in the solution that characterize solvation and association. It is shown that the local distribution of the solvent molecules in the polychloroprene solution differed only slightly from the average over the volume, while the process of solvent association predominated in the solution of fluorosiloxane rubber.