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Organic phase change materials (PCMs) have received increasing attention for their applications in the fields such as solar energy storage and thermal management. Low thermal conductivity is a major key issue that hinders their practical applications. It has become a research hotspot to investigate the three-dimensional (3D) network method to improve the thermal performance of organic PCMs compared with the traditional blending method. Thermally conductive fillers form a 3D network in the resin matrix, which can enrich the thermal conductive pathway and effectively enhance the thermal conductivity. This paper mainly summarizes the research progress, preparation methods and influencing factors of composite PCMs, focusing on the methods of constructing 3D thermal conductivity network. It is hoped to provide reference or suggestion for the preparation of novel PCMs. [ABSTRACT FROM AUTHOR]

Lightweight carbon fiber/carbon composites (CFC) are widely used in solar silicon furnace, semiconductor long crystal furnace and other high-temperature equipment due to its superior low thermal conductivity, low expansion coefficient, high purity, good mechanical properties, and high temperature resistance. In this paper, the lightweight chopped CFC was prepared by the method of liquid phase dispersion of chopped carbon fibers-vacuum filtration-curing molding-high temperature carbonization and graphitization. The thermal conductivity of lightweight chopped CFC with different densities (0.12, 0.16 and 0.18 g/cm3) was studied, and the thermal conductivity of lightweight chopped CFC at high temperature was also studied. The results show that the thermal conductivity (1000 °C) of the chopped CFC gradually increases with the increasing density from 0.179 W/(mK) (0.12 g/cm3) to 0.190 W/(mK) (0.16 g/cm3), 0.282 W/(mK) (0.18 g/cm3), indicating that with the increasing density, the thermal conduction path of the carbon fiber increases, the thermal conductivity of the CFC material increases, and then the thermal insulation performance decreases. In addition, with the increasing temperature, the phonon vibration increases, the thermal conductivity of the CFC material also increases, and then the thermal insulation performance decreases. [ABSTRACT FROM AUTHOR]

As one of the most effective energy storage compounds, phase change materials (PCMS) play an important role in energy conservation and storage. However, the inherent poor thermal conductivity and liquid leakage of PCMS seriously limit their practical application. Polyethylene glycol·calcium chloride (PEG·CaCl2) phase change materials filled with three-dimensional carbon fiber network were prepared by liquid phase impregnation and hot pressing molding method. The experimental results show that carbon fiber network (CF felt) and PEG·CaCl2 complex structure increase the thermal conductivity and stability. The in-plane thermal conductivity of PEG·CaCl2/CF composite (47.73% carbon content) is 0.97 W/mK, about 103% higher than that of PEG. PEG·CaCl2/CF composite does not present leakage even heating at 80 °C for 45 min (35 °C higher than the melting point of pure PEG), showing low leakage ability. High thermal conductivity, low leakage and low density of this composite suggest a promising route for thermal storage applications. [ABSTRACT FROM AUTHOR]

Simply filling the metal foam as a thermally conductive filler into the polymer matrix can improve the thermal conductivity of the polymer matrix, but it still cannot greatly improve the thermal conductivity of the composites. In this paper, the epoxy resin/copper foam-nickel (EP/CF-Ni) composite thermal conductive material was prepared by a combination of electroplating and vacuum liquid impregnation. The deposition of nickel increases the heat dissipation area of the copper foam and at the same time widens the heat conduction path of the materials. By comparing EP/CF with different pores and EP/CF-Ni with different deposition times, it was found that the thermal conductivity of EP/CF-Ni composites could reach 5.215 W/(mK) at 7.3 wt% nickel deposition, which enhanced 2507% and 75% compared to pure epoxy and copper foam matrix composites, respectively. The deposition of nickel further improves the wear resistance of the composite. This experiment reveals the synergistic effect of thermal conductivity of metallic Ni and 3D copper foam, and provides some reference opinions for the field of thermal conductivity of metallic foam. [ABSTRACT FROM AUTHOR]