Both the density and the specific volume as well as the glass transition or crystalline melting point can be determined from the pvT-diagrams.

Here, the crystalline melting point $T_K$ is defined by the point of inversion of the specific volume function in the pvT-diagram. The glass transition point $T_G$ can be determined as the point of intersection of the tangents to the upper and lower volume function. The temperature-dependent density of the melt is described by the following straight-line equation:

Density function: \[ρ = ρ_0 - ρ_m \cdot T\]

If only one density value is available, it must be ensure that this value corresponds to the melt temperature. Otherwise the value $ρ_0$ at $0 °C$ should be entered. In order to simplify the data input it is alternatively possible to enter a temperaturedependent change in the specific volume $v$ by aid of a switch.

Volume function: \[v = v_0 + v_m \cdot T\]

The two characteristic values $v_0$ und $v_m$ can also be established by the pvT-diagram. The values are to be established at a medium pressure corresponding to the process.

The compressibility factor kappa influences the specific volume or rather the density in dependence of the pressure. The value refers to an average temperature and an average pressure of the pvT-data. Changing the specific volume by the pressure is described with the following equation.

\[kappa = - \frac{1}{v} (\frac{dv}{dp}) _{T=const}\]

The value kappa can be imported directly from PAM or entered manually. If 0 is entered as the value for kappa, the specific volume or rather the pressure is calculated without considering the pressure.

In addition to this, the solid and bulk density can be entered.

Platzhalter Abbildung 5.11: Eingabemaske Dichten