Empirical Determination of the Internal Energy of Polyethylene based on the Pressure-Volume-Temperature-Entropy Equation of State

Abstract

The internal energy, U, of polyethylene (PE) was determined by the relations that and the pressure-volume-temperature-entropy equation of state (P-V-T-S Eos) evaluated by the experimental P-V-T data and Cp at 1 atm for PE where CV is the isochoric heat capacity, is the thermal pressure coefficient and CP is the isobaric heat capacity. The 3-dimensional (3D) plot, 3D plot, with the three axes, x = VU, y = SU, z = TU expressed by the 3D (VU , SU , TU ), the 3D (TU, PU. SU ) or the 3D (TU , VU, PU ) at constant U in PE were determined where the four variables, PU , VU , TU , and SU were determined under U being constant. The P-V-T-S behaviors under the iso-internal energy process where U is constant were monitored by the 3D (VU, SU, TU ). The 3D (V, T, P) plot for PE under were expressed by a line not a plane