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

Optimizing Electromagnetic Interference Shielding of Ultrathin Nanoheterostructure Textiles through Interfacial Engineering

“…We chose SiC nanowhiskers to decorate CC textile for the following reasons: SiC semiconductor possesses a wide band gap with high carrier mobility, which facilitates the formation of Schottky barriers with metals. In addition, SiC-based composites exhibit good thermal performance. − Especially, one-dimensional SiC nanomaterials present unique mechanical properties such as high strength, high hardness, and good flexibility . For instance, the SiC nanowires are stretchable and could be extended by more than 200% .…”

Enhancement of Isotropic Heat Dissipation of Polymer Composites by Using Ternary Filler Systems Consisting of Boron Nitride Nanotubes, h-BN, and Al2O3

“…h-BN, an analogue of layered graphite, acts as a promising thermal transport-inducing filler mainly due to its high thermal conductivity, which approaches ∼300 W/mK, with other advantageous attributes such as high elastic modulus, high electrical insulation, relatively low dielectric coefficient, and low density, which are highly appreciated in numerous fields. ,− However, due to the planar nature of h-BN, most of the h-BN-based composites showed an anisotropic characteristic, producing superior in-plane and inferior through-plane thermal conduction behaviors. To instigate an effective heat dissipation behavior, one should thoroughly consider both in-plane and through-plane thermal conductivities.…”

Dopamine-Decorated Ti3C2Tx MXene/Cellulose Nanofiber Aerogels Supported Form-Stable Phase Change Composites with Superior Solar–Thermal Conversion Efficiency and Extremely High Thermal Storage Density

“…Recently, the encapsulation of PCMs into three-dimensional (3D) porous materials, such as aerogels, has been regarded as the most accessible and effective strategy for fabricating form-stable PCMs. − These interconnected 3D porous aerogels with an ultrahigh surface area and extremely low density could well-support PCMs and avoid liquid leakage because of strong capillary force and surface tension. Among various aerogels, cellulose-based aerogel draws tremendous attentions due to being readily available, biodegradable, sustainable, and environmentally friendly. − Nevertheless, the poor solar–thermal conversion performance of cellulose and sugar alcohols seriously limits efficient photons harvest, conversion, and storage.…”