Transport, Thermodynamic, and Thermophysical Properties of Aqueous Mixtures of Poly (Ethylene Glycol): Experimental and Modeling

Abstract

Density (ρ) and viscosity (η) of aqueous mixture containing poly(ethylene glycol)s (PEG)s with seven nominal molecular masses (1500 g·mol⁻¹, 2000 g·mol⁻¹, 3000 g·mol⁻¹, 4000 g·mol⁻¹, 6000 g·mol⁻¹, 8000 g·mol⁻¹, and 20 000 g·mol⁻¹) have been experimentally measured at five temperatures (288.15 K, 293.15 K, 303.15 K, 308.15 K, and 313.15 K) and five concentrations of PEG (0.05, 0.10, 0.15, 0.20, and 0.25 mass fraction), at atmospheric pressure (0.1 MPa). Several thermophysical properties, including the apparent specific volume ($V_{\varphi }$), excess molar volume ($V_{m}^{E}$), coefficient of thermal expansion ($\upalpha_{\text{P}}$), excess coefficient of thermal expansion ($\upalpha_{P}^{E}$), were calculated using experimental data. The obtained excess parameters have been used to investigate the inter-intra molecular interactions in the liquid solutions. Moreover, the S-Wilson-NRF and modified UNIQUAC-FV thermodynamic models have been extended for the representation of the density of binary mixtures of PEG + water solutions and the original UNIFAC-VISCO, Z-UNIFAC-VISCO, UNIFAC-Sheng-VISCO, Chain-FV-VISCO, and UNIFAC-vdW-FV-VISCO thermodynamic models were applied to calculate the viscosity of PEG solutions. In addition, an alternative modeling approach in the form of artificial neural networks, developed with an evolutionary algorithm, namely differential evolution algorithm, was used for prediction of density of the mentioned solutions. The results of the neural network model show that this model is suitable for both correlation and prediction of the density of PEG solutions at different PEG molar masses, temperatures, and concentrations.