Polyimide foam composites with nano-boron nitride (BN) and silicon carbide (SiC) for latent heat storage

Abstract Leaching and instability in wax-based phase change materials (PCMs) are serious application problems. Herein, we developed paper-like (~ 100 µm) flexible, composite PCMs by hydraulic compression of 1-cm-thick polyimide foams between an aluminum foil and a (nano) ceramic composite Parafilm®. An unfilled PCM film placed between the foam and the aluminum surface ensured strong adhesion between the collapsed foam and the metal. Different concentrations of nano-BN and micro-SiC particles were compounded into Parafilm® in order to optimize the thermal performance. Based on infrared imaging, the monoliths containing 30 wt% micro-SiC outperformed all other systems including BN/SiC hybrids. The next best thermal performance was observed with the 60 wt% nano-BN composite. Due to compression, the cellular structure of the polyimide foams collapsed irreversibly while being impregnated by the PCMs from both sides. High- k fillers improved impregnation into the collapsed foam and enabled excellent shape stability and leakage prevention. Graphical abstract