Thermal properties of crystalline polymers at low temperatures

This chapter examines some recent experimental results on the thermal properties of crystalline polymers (e.g., heat capacity, thermal diffusivity and conductivity), and also the thermal expansion and Grueneisen-function of semicrystalline polyethylene (PE) and single crystalline polydiacetylene (PTS) in the temperature range from 3 to 300K. Discusses the heat capacity of semicrystalline PE with its dependences from crystallinity and temperature; some related effects arising from the model of the ideal polymer lattice with recent Cp data on a PTS-single crystal; a comparison of thermal conductivity measurements on PE and PTS; and the first results of thermal expansion measurements on PE and PTS. Finds that the thermal expansion of semi-crystalline PE above 120K and below 50K is strongly affected by its amorphous phase