Processable and recyclable polyurethane/HNTs@Fe₃O₄ solid–solid phase change materials with excellent thermal conductivity for thermal energy storage

Abstract

The permanently chemically cross-linking solid-solid phase change materials (SSPCMs) were designed to solve the problem of leakage and poor shape stability during the whole process of phase transformation. However, these materials lead to environment pollution and resources waste because of the non-recyclability. Therefore, a SSPCMs was fabricated using dynamic thermal reversible Diels-Alder bonds. The prepared SSPCMs exhibited excellent shape, heat storage stability, and reliability and reprocessed ability, resulting from dynamic Diels-Alder bonds. Moreover, the Halloysite nanotubes decorated with Fe 3 O 4 nanoparticles (HNTs@Fe 3 O 4 ) were used to enhance the thermal conductivity of SSPCMs. When the filler content was 0.5 wt%, the best integrated properties (phase change properties and thermal conductivity) of the SSPCMs were obtained, it had the highest melting and freezing phase change enthalpies about 116.8 and 127.2 J/g, and thermal conductivity value, 0.223 W/m K, which was 101% higher than pure SSPCMs. Hence, the prepared SSPCMs can be considered as promising save-energy, friendly-environment thermal management materials.

Morphological engineering of SiO2 interlayer towards meliorative dielectric and thermal properties in β‐SiCw@SiO2/PVDF composites

“…The calcined β‐SiC w @SiO 2 /PVDF exhibits improved TC in comparison to raw β‐SiC w ‐0/PVDF due to the formation of hydrogen bonds between the SiO 2 shell and host PVDF, this enhances the interfacial compatibility of the β‐SiC w filler and PVDF matrix, as schematically depicted in Figure 10C. Compared to the β‐SiC w ‐0/PVDF, the long‐range migration of electron transmission in raw β‐SiC w ‐1/PVDF and β‐SiC w ‐3/PVDF is obviously restrained 48,49 . This is because the SiO 2 shell becomes increasingly dense and has a better electron‐blocking effect as the calcination temperature increases.…”

“…Compared to the β-SiC w -0/PVDF, the long-range migration of electron transmission in raw β-SiC w -1/PVDF and β-SiC w -3/PVDF is obviously restrained. 48,49 This is because the SiO 2 shell becomes increasingly dense and has a better F I G U R E 1 0 (A) A comparison of the thermal conductivity (TC) of the composites with various fillers at various calcination temperatures, (B) describes infrared thermograms of various composites, and (C) schematic diagram of the models of heat transfer mechanism of various composites. 51…”

Synthesis and Properties of Dynamic Crosslinking Polyurethane/PEG Shape-Stable Phase Change Materials Based on the Diels–Alder Reaction

“…Currently, with the increase of environmental standards and energy demand, it has great practical significance to realize the reuse and reprocessing of PCMs for thermal management applications. In fact, development of stimulus response dynamic networks has already improved novel phase change materials with excellent recyclable performance. , For example, Lei and coworkers have reported a series of PCMs with a dynamic crosslinked structure, including dynamic Diels–Alder (DA) bonds, disulfide covalent bonds, metal–ligand coordination, and oxime carbamate bonds . Wang et al ,, adopted furan/maleimide Diels–Alder (DA) and hydrogen bonds as reversible units to synthesize SSPCM composites.…”

Fully Closed-Loop Recyclable Thermosetting Polythiourethane Microspheres and Their Application in Efficient Fabrication of Composites with Segregated Structures

“…CANs rely on dynamic covalent bonds that can break/reform and recombine either autonomously or with appropriate stimuli (esp. light , and heat − ), endowing polymers with unprecedented properties, such as self-healing, ,, recyclability, , weldability, and reprocessabIlity. − So far, many dynamic covalent bonds, such as Diels–Alder, , transesterification, , carbamate bonds, thiol–ene click reactions, disulfide bonds, − thiocarbamate bonds, − thiol–anhydride, transimination, boronic esters, , siloxane exchange, and hindered urea bonds, have been applied to design the thermosetting polymers with various types of CANs. , …”