Thermal expansion and thermal conductivity of Torlon at low temperatures

We measured the expansion coefficient of Torlon 4203 (polyamide-imide) as a function of temperature between 4.2 and 295 K. The thermal expansion is lower than that of most polymers. The thermal conductivity k between 0.1 and 5 K was also measured: below 1 K, a quadratic dependence on temperature of k was found, as predicted by the tunnelling model, while the behaviour shown by our data above 1 K suggests the presence of a plateau.