Exploration of the intermolecular interactions in polyethylene glycol 400 + alkyl methacrylate mixtures at ambient temperatures by means of thermophysical and spectroscopic methods

• Reports new ρ and u data of PEG 400 + MMA/EMA binary mixtures • Reports calculated values of the excess properties of PEG 400 + MMA/EMA mixtures • Correlates excess properties with interactions in these PEG 400 + MMA/EMA mixtures • The PEG 400 - methacrylate interactions follow order: MMA > EMA • The FT-IR spectra of equimolar mixtures was recorded and correlated with interactions Thermophysical and spectral analysis for binary systems comprising polyethylene glycol 400 and alkyl methacrylate have been carried in this study with an objective to understand the molecular interactions therein. For this purpose, experimental measurements of densities, ρ and speeds of sound, u for polyethylene glycol 400 (PEG 400) with methyl methacrylate (MMA) and ethyl methacrylate (EMA) binary systems were carried out across the entire mole fraction range and at temperatures, T = (293.15 to 323.15) K and pressure, p = 100 kPa. From the measured primary properties, various excess functions and deviation parameters such as the excess molar volume, excess isentropic compressibility, excess molar isentropic compressibility, excess intermolecular free length, and excess speed of sound were calculated and the compositional dependence of each of the parameters were correlated with Redlich-Kister equation. The partial molar and excess partial molar properties (volume and compressibility) of the constituent molecules in the mixture at all mole fractions, and at infinite dilution were computed. The change in these parameters with composition and temperature has been interpreted and compared with each other to understand the interactions in these mixtures, and the PEG-alkyl methacrylate interactions follow the sequence: MMA > EMA. The u values have been estimated theoretically by means of scaled particle theory and compared with the experimental findings. Furthermore, FT-IR spectra of pure PEG 400, MMA, EMA and their equimolar mixtures were also recorded and analysed to support the conclusions concerning the prevailing interactions between unlike molecules from the thermophysical properties.