Approach to measure in-plane thermal conductivity of thin polymer films

摘要

Anisotropic, in-plane thermal conductivity of thin polymeric films is important to a number of applications such as metalized film capacitors for which film thermal conductivity is critical to the thermal stability of DC bus link capacitors and pulse discharge capacitors used in repetitive applications such as rail guns. When large amounts of film are available, thermal conductivity can be measured using planar transducers applied to the edge of a reel of film. A need exists for a method that can measure in-plane thermal conductivity on small samples of developmental film. Measurement of a small piece of free-standing film is difficult as a result of the low sample thermal capacitance and in-plane thermal conductance relative to its surface area which radiates to the ambient. While the approach proposed in this paper may or may not be practical, given that no practical method has been found, analysis of this method is useful.