SOME PECULIARITIES OF THERMODYNAMIC BEHAVIOR OF OLIGOMERIC MIXTURES WITH SPECIFIC INTERACTIONS BETWEEN COMPONENTS

Using inverse gas chromatography, the temperature and concentration dependences of the interaction parameter χ23 were estimated for mixtures of various oligomers capable of specific interaction. Mixtures of polyethylene glycol with polypropylene glycol and polyethylene glycol adipate were studied, including mixtures of polyethylene glycol fractions of different molecular weights. It was found that there is a maximum and a minimum in the temperature dependence of χ23, and the bimodal character phase diagrams was established. Experimental data were explained by aggregation or association phenomena in mixtures. The comparison of experimental values of χ23 with those calculated on the basis of the new Flory theory shows essential differences, especially for enthalpy and entropy contributions, this being explained by the specific interaction between components. © 1979.