  This work covers an ab initio calculation of thermodynamic, transport, and
optical properties of plastics of the effective composition CH$_2$ at density
0.954 g/cm$^3$ in the temperature range from 5 kK up to 100 kK. The calculation
is based on the quantum molecular dynamics, density functional theory and the
Kubo-Greenwood formula. The temperature dependence of the static electrical
conductivity $\sigma(T)$ has a step-like shape: $\sigma(T)$ grows rapidly for 5
kK <= $T$ <= 10 kK and is almost constant for 20 kK <= $T$ <= 60 kK. The
additional analysis based on the investigation of the electron density of
states (DOS) is performed. The rapid growth of $\sigma(T)$ at 5 kK<= $T$ <= 10
kK is connected with the increase of DOS at the electron energy equal to the
chemical potential $\epsilon = \mu$. The frequency dependence of the dynamic
electrical conductivity $\sigma_1(\omega)$ at 5 kK has the distinct non-Drude
shape with the peak at $\omega \approx 10$ eV. This behavior of
$\sigma_1(\omega)$ was explained by the dip at the electron DOS.
