Pressure volume temperature studies

Olabisi, 0. Simha, R., "Pressure-Volume-Temperature Studies of Amorphous and Crystal-lizable Polymers. I. Experimental," Macromolecules, 8, 206 (1975). 

Olabisi, O., Simha, R. Pressure-volume-temperature studies of amorphous and crystallizable polymers. I. Experimental, Macromolecules 8(2), 206-210 (1975)... 

Dlubek, G., Shaikh, M. Q., Raetzke, K., Faupel, F., Pionteck, J., and Paluch, M. (2009) The temperature dependence of free volume in phenyl salicylate and its relation to structural d5mamics A positron annihilation lifetime and pressure-volume-temperature study, J. Chem. Phys. 130, 144906. 

Zienkiewicz OC, Taylor RL, Zhu JZ (2005) The Finite Element Method Its Basis and Fundamentals, 6th edn. Elsevier Butterworth-Heinemann, Burlington Zoetelief WF, Douven LFA, Ingen-Housz AJ (1996) Residual thermal stresses in injection molded products. Polym Eng Sci 36 1886-1896 Zoller P, Fakhreddine YA (1994) Pressure-volume-temperature studies of semi-crystalline polymers. Thermochim Acta 238 397-415... 

DL1 Dlubek, G., Pionteck, J., Sniegocka, M., Hassan, E.M., and Krause-Rehberg, R., Temperature and pressure dependence of the free volume in the perfluorinated polymer glass CYTOP A positron lifetime and pressure-volume-temperature study (experimental data by G. Dlubek), J. Polym. Sci. Part B Polym. Phys., 45, 2519,... 

We generally distinguish between two methods when the determination of the composition of the equilibrium phases is taking place. In the first method, known amounts of the pure substances are introduced into the cell, so that the overall composition of the mixture contained in the cell is known. The compositions of the co-existing equilibrium phases may be recalculated by an iterative procedure from the predetermined overall composition, and equilibrium temperature and pressure data It is necessary to know the pressure volume temperature (PVT) behaviour, for all the phases present at the experimental conditions, as a function of the composition in the form of a mathematical model (EOS) with a sufficient accuracy. This is very difficult to achieve when dealing with systems at high pressures. Here, the need arises for additional experimentally determined information. One possibility involves the determination of the bubble- or dew point, either optically or by studying the pressure volume relationships of the system. The main problem associated with this method is the preparation of the mixture of known composition in the cell. 

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 ... 

The virial equation of state discussed in Section 7.2 is applicable to gas mixtures with the condition that n represents the total moles of the gas mixture that is, n = f= l n,. The constants and coefficients then become functions of the mole fractions. These functions can be determined experimentally, and actually the pressure-volume-temperature properties of some binary mixtures and a few ternary mixtures have been studied. However, sometimes it is necessary to estimate the properties of gas mixtures from those of the pure gases. This is accomplished through the combination of constants. 

The virial coefficients can be determined from studies of the pressure-volume-temperature relations of gases. A graphical method for determining the fugacity may be illustrated by the use of the equation of state... 

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 properties of gases that are most easily observed are the relationships among pressure, volume, temperature, and mass. If you have ever inflated a balloon, baked a cake, or slept on an air mattress, you have observed how these properties are related. Because the laws of gases were developed from the study of their properties and behavior, it is now possible to predict the physical behavior of gases by the application of these laws. 

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. 

Next, we study the relationship among pressure, volume, temperature, and amount of a gas in terms of various gas laws. We wiU see that these laws can be summarized by the ideal gas equation, which can be used to calculate the density or molar mass of a gas. (5.3 and 5.4)... 

Estimates of equilibrium melting temperatures of PCL crystallites were made, for various binary and ternary systems, with the aid of Hoffman-Weeks plots. The observed melting points of PCL were between 55 ° C and 65 ° C and varied by about 3 °C with changes in from 38 °C to 48 °C. From the melting-point depressions, as a function of composition and pressure-volume temperature data, Kim and Paul estimated equation-of-state parameters. During the course of this study Kim and Paul determined specific volume data for PCL at a series of hydrostatic pressures (Fig.51) [87]. 

Thermomechanical and dynamic mechanical tests represent what may be the most useful and yet least understood techniques in modern thermal analysis. Three techniques are commonly used to study polymers (1) thermomechanical analysis (TMA), (2) pressure-volume-temperature PVT) measurements, and (3) dynamic mechanical analysis (DMA). 

Thus far we have concentrated on the behavior of pure gaseous substanees, 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... 

All of the pressure-volume-temperature relationships for gases that we have studied may be combined into a single relationship called the combined gas law. This expression is useful for studying the effect of changes in two of these variables on the third as long as the amount of gas (number of moles) remains constant. 

Out-of-plane linear CTEs (ax) were calculated from the difference between the volumetric CTE and the sum of the in-plane linear CTEs (a and oj. Volumetric CTEs were obtained from a pressure-volume-temperature (PV technique based on Bridgeman bellows. Although the linear CTEs vaiy significantly with processing, the volumetric CTE is essentially constant, independent of molecular orientation. For all of the polyimide films studi the out-of-plane linear CTEs (a ) were higher than the in-plane linear CTEs (a, and tty). 

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