Thermal conductivity of Kapton-derived carbon

Abstract Heat treatment of translucent Kapton ® HN polyimide films conducted in inert atmosphere yields black residues. Micro-Raman spectroscopy revealed that the residues obtained between 600°C and 1200 °C are mainly constituted of disordered carbon. Aside its standard application in the structural identification of carbon, the Raman technique has also been used as a means of evaluating the thermal conductivity of Kapton-derived carbon. The aim of this study is to know whether such a tool can also be appropriate for disordered carbon with coherent diameters lower than 2 nm and with variable quantities of heteroatoms (H, O, N). To achieve this aim, a comparative study was undertaken using two other conventional techniques, namely laser flash analysis and photothermal radiometry. It has been found that thermal conductivity increases linearly with the heat-treatment temperature of Kapton and reaches 1.905 Wm −1 K −1 for the film heat-treated at 1200 °C. The comparison of the experimental results shows that the Raman thermometry is particularly sensitive for sp 2 carbon and predicts quite well the general trend of thermal conductivity of materials. However, the precision is rarely better than 20%.