Experimental Investigation of Interactions and Thermodynamic Properties of Poly(ethylene glycol) 200/400 + Dimethyl Adipate/Dimethyl Phthalate Binary Mixtures

Density rho, viscosity eta, and refractive index n(D) have been experimentally measured for four binary mixtures dimethyl adipate + poly(ethylene glycol) 200, dimethyl adipate + poly(ethylene glycol) 400, dimethyl phthalate + poly(ethylene glycol) 200, and dimethyl phthalate + poly(ethylene glycol) 400 in the temperature range T = (288.15 to 323.15) K with a temperature step of 5 K and at atmospheric pressure. Excess molar volumes V-E, viscosity deviations Delta eta, and deviations of refractive index Delta n(D) were calculated from experimental data and fitted using Redlich-Kister polynomial. Fourier-transform infrared analysis of binary mixtures and corresponding pure components was performed at 298.15 K in order to gain insight into the molecular structure of mixtures and possible intra- and intermolecular interactions. Performed IR analysis confirms an absence of intermolecular interactions between unlike compounds. Consequently, the nonideal behavior of mixtures is contributed to geometrical packing or dispersion forces of different species.