Carbon Nanotube/Polyamic Acid Bilayer-Supported Composite Phase-Change Materials With Integrated Insulation and Thermal Conductivity Functions

Abstract

Carbon aerogel supported phase change materials (PCMs) can confer multifunctional properties to ordinary PCMs and meet specific requirements in extreme environments. In this study, composite phase change materials (CPCMs) with integrated insulation and thermal conductivity functions were successfully developed through the physical integration of a thermal insulation layer and a thermal conductivity layer. The structurally stable carbonized polyimide (C-PI)/carbon nanotubes (CNTs) aerogel acts as the thermal conductivity layer substrate. The aerogel obtained from a polyamic acid salt (PAS) composite with carboxymethyl cellulose (CMC) was used for the thermal insulation layer. Then, polyethylene glycol was vacuum-impregnated into the integrated aerogel to prepare CPCMs with integrated insulation, thermal conductivity, and thermal energy storage functions. When the mass ratio of CNTs to PAS was 2, the enthalpy reaches 160.3 J/g and the PEG loading reaches 95.56%. Moreover, the presence of CNTs increased the thermal conductivity of the thermal conductive layer to 0.433 W/m K. In addition, the bilayer CPCMs can conduct heat quickly and also have a good thermal insulation effect. The all-in-one material achieves a perfect combination of dual functions and provides a new solution for thermal management of power devices. Furthermore, the bilayer CPCMs also have great application potential in the field of infrared stealth.