Path: Main menu > Material > New polymer… Tab: Thermodynamic data



Path: Main menu > Material > Edit material (file)… Tab: Thermodynamic data



Just as the material data mentioned before the thermodynamic Data are entered and edited in the window Material Data. They are placed on the tab Thermodynamic Data.

Path: Main menu > Material > New polymer… Tab: Thermodynamic Data



Path: Main menu > Material > Edit material (file)… Tab: Thermodynamic Data

The function curve of the specific heat capacity cp at ambient pressure is presented in the figure for amorphous and semi-crystalline thermoplastics. In the molten range, the specific heat capacity follows an almost linear course and can thus be described by a straight-line equation:

$$c_p = c_{p0} + c_{pm} \cdot T$$

Path: Main menu > Material > New polymer… Tab: Thermodynamic Data



Path: Main menu > Material > Edit material (file)… Tab: Thermodynamic Data

The specific enthalpy is obtained from the integral of the specific heat capacity $c_p(T)$ between the limits T₁ and T₂:

$$\Delta h = \int_{T_1}^{T_2} c_p(T) \, dT$$

In this way the quantity of heat (per mass unit) is obtained which is needed to increase the temperature of the polymer from T1 to T2. In case of an amorphous material a steeper increase of the enthalpy is seen with the rising temperature up from the glass transition point Tg as for a semi-crystalline material.

In contrast semi-crystalline materials display a step-by-step increase conditional on the phase change. The additional quantity of heat is denoted as the melting enthalpy ΔhA. The figure shows the specific enthalpy as a function of temperature for both types of polymers, amorphous and semi-crystalline ones.

If an amorphous thermoplastic is specified, the entering sheet for the melting enthalpy is not available. In the case of semi-crystalline thermoplastics, the enthalpy increase Δh is made up of the enthalpy increase of the solid enthalpy ΔhF and the melting enthalpy ΔhA:

• semi-crystalline thermoplastics: $\Delta h = \Delta h_F + \Delta h_A$
• amorphous thermoplastics: $\Delta h = \Delta h_F$

Path: Main menu > Material > New polymer… Tab: Thermodynamic Data



Path: Main menu > Material > Edit material (file)… Tab: Thermodynamic Data

In the case of thermal conductivity, it is necessary to distinguish between steady-state and non-steady-state temperature fields. With steady-state temperature fields, only the thermal conductivity l is available as a material value. This is temperature-dependent and higher for semi-crystalline materials than for amorphous ones, see figure.

Thermal conductivity: $\lambda(T) = \lambda_0 + \lambda_m \cdot T$

The value $\lambda_0$ which has to be entered represents the value obtained from the straight line that describes the molten range at 0 degrees. The gradient for the thermal conductivity can also be negative and must then be entered with a negative sign. The effective thermal conductivity of the solid is required for the melting calculation. For purposes of determining this value, it is necessary to enter the thermal conductivity of the solid. The melting point $T_{k,g}$ must also be entered on this mask. In the case of semi-crystalline materials, this temperature is interpreted as the crystalline melting point $T_k$ and in the case of amorphous polymers, as the glass transition point $T_g$.