Thermodynamic Properties and Physical–Chemical Transformations of Polymer Materials at High Temperatures and Pressures

A semiempirical equation-of-state model for polymer materials over a wide range of thermodynamic parameters is proposed, allowing for the transformation of compounds at high dynamic pressures. Equations of state for polystyrene, polyimide, and poly(m-phenylene isophthalamide) are developed, and a critical analysis of calculated results in comparison with the set of available highenergy density experimental data is made.