Modification of Tao-Mason equation of state: application to polymer melts

Abstract

The present work addresses a simplified procedure for the calculation of certain parameters in the Tao-Mason (TM) equation of state (EOS) needed to calculate the volumetric properties of polymer melts using surface tension γ_f and liquid density at freezing temperature ρ_f, with scaling parameters at compressed state and in the temperature range of 298.15 to 423.15 K and pressures up to 200 MPa. The polymers in question are polyethylene glycol (PEG), polypropylene glycol (PPG), polypropylene (PP) and polyvinyl choloride (PVC). The calculated densities were in good agreement with the ones obtained from the experimental specific volumes as well as polymer chain-of-rotator (PCOR) EOS. The accuracies were found to be of the order of 1.5%. Finally, the modified TM EOS was further assessed through comparing with the Ihm-Song-Mason (ISM) EOS.

Keywords:

• equation of state
• polymer melts
• statistical mechanics
• surface tension
• volumetric properties

Acknowledgements

The authors are grateful to the Shiraz University of Technology, Shiraz University and Payame Noor University for supporting this project.