Prediction of PVT properties of polymer melts with a new group-contribution equation of state

A new group-contribution modified cell model equation of state (GCMCM EOS) has been developed to predict pressure–volume–temperature (PVT) properties of polymer melts. The equation uses monomer group contributions to estimate the characteristic parameters in the modified cell model (MCM EOS) proposed by Dee and Walsh [G.T. Dee, D.J. Walsh, Macromolecules 21 (1988) 811–817] for polymer molecules. Three molecular parameters per group were determined for 20 different groups. Average prediction error of specific volumes was 0.67% for 32 homopolymers and 1.01% for 20 copolymers and blend polymers over a wide range of temperature (277–671 K) and pressure (0.1–200 MPa). The average prediction error of PVT by GCMCM EOS was less than half of that by Parekh and Danner [V.S. Parekh, R.P. Danner, J. Polym. Sci., Part B 33 (1995) 395–402]. Furthermore, if one specific volume datum at atmospheric pressure is used, the average prediction error of PVT by GCMCM EOS could be reduced to 0.27% for the homopolymers and 0.34% for the copolymers and blend polymers.