Experimental Study on Polymer–Polymer Interfacial Thermal Resistance

Abstract

This study presents an experimental measurement of interfacial thermal resistance (ITR) at polymer–polymer interfaces using a multi-layered bulk sample approach. ITR is commonly measured using thin-film techniques, but new advancements enable testing in bulk materials with multilayered structures. However, traditional multilayer fabrication is often resource-intensive and lacks consistency. This study introduces a simple rotational overlapping method for fabricating multi-layered polymer samples for bulk ITR measurement. Combining numerical simulations with experimental validation, researchers optimize layer overlapping conditions using measured viscosity data of high-density polyethylene (HDPE), polypropylene (PP), and polylactic acid (PLA). Samples are fabricated at viscosity-matching temperatures, and shear forces from stirring disks create uniform layer patterns. Computational fluid dynamics (CFD) simulations elucidate the layer formation mechanism, enabling the fabrication of samples with over 112 layers within a 4.6 mm thickness. ITR testing reveals a direct correlation between layer number and thermal resistance. PE-PP samples exhibit an average ITR of 9.58 × 10⁻⁶ K m² W⁻¹, with a 10.32% increase in resistance from 38 to 112 layers. Similarly, PE-PLA samples with an ITR of 1.31 × 10⁻⁵ K m² W⁻¹ show a 2.8% increase from 5 to 23 layers. Overall, The experimental procedure provides valuable data to advance the understanding of ITR in polymer–polymer interfaces.