Acoustical study of molecular interactions in polymer solutions through various thermodynamical parameters and Flory's theory at 298.15 K

Abstract

This study intends to portray the nature of polymer solutions by ultrasonic velocity and density data. Acoustical parameters, such as relaxation strength, relative association, molecular constant, fractional free volume, available volume, Beyer's non-linearity parameter, internal pressure, van der Waals’ constants and molecular radius have been computed for the binary mixtures of PEG400 + methanol, PEG400 + ethanol, PPG400 + ethanol and PPG400 + 2-propanol systems at 298.15 K. Flory's theory has been used for computing ultrasonic velocity, surface tension, thermal expansion coefficient, thermal conductivity, excess heat capacity and excess isothermal compressibility. Isothermal compressibilities of mixtures have been theoretically evaluated using different theories. A new relation has been proposed by us for evaluating excess molar volume using ultrasonic velocity of the mixture which gives fairly good result when compared with the experimental values. Excess molar volume has been calculated using Flory's theory and Prigogine–Flory–Patterson theory. The partial molar volume and its excess value at infinite dilution have also been evaluated.

Keywords:

• polyethylene glycol 400
• polypropylene glycol 400
• Flory's theory
• excess molar volume

Acknowledgements

One of the authors (M.G.) is grateful to UGC New Delhi for providing funding for this major research project.