PRESSURE VOLUME TEMPERATURE RELATIONSHIPS FOR POLYMERIC LIQUIDS - A REVIEW OF EQUATIONS OF STATE AND THEIR CHARACTERISTIC PARAMETERS FOR 56 POLYMERS

A review of theoretical equations of state for polymer liquids is presented. Characteristic parameters for six equations of state, as well as parameters for the empirical Tait equation, are given for 56 polymers where pressure-volume-temperature (PVT) data over a wide range of conditions could be found in the literature. New PVT data are presented for four polymers: poly(epichlorohydrin), poly(epsilon-caprolactone), poly(vinyl chloride), and atactic polypropylene. All six equations of state provide adequate fits of the experimental specific volume data for the 56 polymers in the low pressure range (up to 500 bar). The modified cell model of Dee and Walsh, the Simha-Somcynsky hole theory, the Prigogine cell model, and the semiempirical model of Hartmann and Haque, were all found to provide good fits of polymer liquid PVT data over the full range of experimental pressures. The Flory-Orwoll-Vrij and the Sanchez-Lacombe lattice-fluid equations of state were both significantly less accurate over the wider pressure range.