Volume-Pressure-Temperature Relationships

DREISBACH, R. R. (1952) Pressure-volume-temperature Relationships of Organic Compounds, 3rd edn (Handbook Publishers). 

Dreisbach, R.R. Pressure- Volume-Temperature Relationships of Organic Compounds (Sandusky, OH Handbook Publishers, 1952), 349 p. 

Equations of state can be used to calculate gas-liquid equilibria as an alternative to using K-factor correlations. The assumption must be made that the equations of state presented in Chapters 3 and 4 predict pressure-volume-temperature relationships for liquids as well as for gases. 

R. R. Dreisbach, Pressure—Volume—Temperature Relationships of Organic Compounds, Handbook Publishers, Sandusky, Ohio, 1952, pp. 294. 

An increase in the melting point with increasing pressure (0.154 deg per atmosphere) was reported by McGeer and Duus, and the pressure-volume-temperature relationship of polytetrafiuoroethylene above its melting point was studied in more detail by Lupton who found the following equation of state ... 

Zoller, P., "Pressure-Volume-Temperature Relationships of Solid and Molten Polypropylene and Poly(butene-1)," J. Appl. Polym. Sci., 23, 1057 (1979). 

Zoller, P., "A Study of the Pressure-Volume-Temperature Relationships of Four Related Amorphous Polymers Polycarbonate, Polyarylate, Phenoxy, and Polysulfone," J. Polym. Sci., Polym. Phys. Ed., 20, 1453 (1982). 

The pressure-volume-temperature relationship is concisely represented by the compressibility factor,... 

The analytical equations of state used to compute the pressure-volume-temperature relationships are generally one of the following three classes, viz. virial equations of state, cubic equations of state and the Benedict-Webb-Rubin equation or modifications thereof. 

In thermodynamics, the pressure-volume temperature relationships of real gases are described by the equation of state. The compressibility factor from the reduced pressure and temperature can be rearranged from Redlich and Kwong [9] to two constant state equations in the form... 

Correlations for the key volumetric properties (the van der Waals volume and the molar volumes, densities and coefficients of thermal expansion of amorphous polymers) will be developed in Chapter 3 followed by discussions of pressure-volume-temperature relationships and of the effects of crystallinity on the density. 

Equations 13.19 and 13.20 are approximations since k and a are defined in terms of the change of the volume with a change of p or T in the limit of very small p. The complete pressure-volume-temperature relationships must be considered to provide a more accurate description of the pressure dependence of rj at elevated pressures, at the cost of increased complexity of the calculations. It was shown [7] that Equation 13.21 provides a reasonable first approximation for (K/a), so that Equation 13.20 can be rewritten in the even simpler form given by Equation 13.22 ... 

Thus far we have concentrated on the behavior of pure gaseous substances, but experimental studies very often involve mixtures of gases. For example, for a study of air pollution, we may be interested in the pressure-volume-temperature relationship of a sample of air, which contains several gases. In this case, and all cases involving mixtures of gases, the total gas pressure is related to partial pressures, that is, the pressures of individual gas components in the mixture. In 1801 Dalton formulated a law, now known as Dalton s law of partial pressures, which states that the total pressure of a mixture of gases is just the sum of the pressures that each gas would exert if it were present alone. 

FIGURE 15.1 Pressure-volume-temperature relationship for a pure substance (reprinted from Collier and Thome [3] by permission of Oxford University Press). 

PRESSURE VOLUME TEMPERATURE RELATIONSHIP FOR POLYMER MELTS... 

Pressure-Volume-Temperature Relationship for Polymer Melts... 

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