Publication

This research contains both simulation and experimental study of rotational overlapping methods to create multi-layer polymer samples for measuring interfacial thermal resistance (ITR). Our lab group aims to produce polymer-based insulators that are more efficient and require less thickness, achieved through utilizing interfacial thermal resistance of polymer films. To achieve this, we conducted numerical simulations to determine the optimal conditions for layer overlapping using measured viscosity data. Subsequently, we performed experiments using PE, PP and PLA as sample materials. The materials were heated to a temperature where their viscosities matched. Then, a pair of rotating stirring disks were brought into contact with the non-Newtonian molten polymer, generating friction that dragged the polymer melt and created an overlapping layer pattern. We determined the necessary rotation requirements using computational fluid simulation, successfully merging over 100 layers within a 5 mm thickness. We then tested sample materials with different layer numbers to compare their ITR. PE–PP has an average measured ITR of 9.58×10^-6 K⋅m^2/W, and thermal resistance has shown 10.32% increase from 38 layers to 112 layers. On the other hand, PE-PLA has an ITR of 1.31×10^-5 K⋅m^2/W, with a thermal resistance increase of 2.8% from 5 to 23 layers. The results showed that even a small number of overlapping layers can significantly change the thermal behavior of the polymer material. In conclusion, rotational overlapping with ITR could help polymer material to reach higher thermal resistance with given thickness.