EQUATIONS OF STATE OF ORGANIC HIGH POLYMERS
GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV
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The two-parameter solid equations of state, the Murnaghan Equation, the Tait Equation, and a generalized form of the Birch Equation were selected to fit the static pressure-volume isotherms of solid and liquid high polymers. These equations were found to have a wide range of applicability. They can be extrapolated to very high pressure with good accuracy. The first and second derivatives appear to be well behaved. These equations can be used to obtain analytical expressions for the Gruneisen parameter, containing the volume or pressure explicitly and temperature implicitly. They yield values that seem to be in agreement with the latest theoretical deductions. When used with the Kennedy fusion law, these isothermal equations can be used to predict melting temperatures under very high pressures. It has also been shown that these equations can be used to predict the shock compression data, and a discussion of the shock compression data as influenced by the degree of crystallinity of the polymers is given. Along with the PVT properties of polymers, the specific heats CP and Cv of polyethylene, polychlorotrifluoroethylene, and polytetrafluoroethylene under high pressures are evaluated.
- Physical Chemistry