硬脂醇/Co_(3)O_(4)/膨胀石墨复合相变材料的制备及性能

Preparation and properties of stearyl alcohol/Co_(3)O_(4)/expanded graphite composite phase change material

以硬脂醇(SAL)作为相变材料、Co_(3)O_(4)/膨胀石墨(EG)作为支撑材料,通过熔融共混-压制成型制备了一种复合相变材料(PCMs)SAL/Co_(3)O_(4)/EG-P。EG的添加用于改善PCM的导热性能,同时采用ZIF-67煅烧后得到的Co_(3)O_(4)对其进行了化学改性。采用SEM对Co_(3)O_(4)/EG-P的结构进行表征。结果表明,Co_(3)O_(4)/EG具有三维耦合网络和分级多孔结构,EG可以有效防止金属有机骨架衍生材料结构的坍塌和团聚。采用SEM、DSC和红外成像仪对复合PCMs的形貌和热性能进行了分析。结果表明,随着Co_(3)O_(4)和EG的质量比从1∶1到1∶8,复合PCMs的导热系数呈现上升趋势。当m(Co_(3)O_(4))∶m(EG)=1∶8时,复合PCMs的熔化温度为51.26℃,潜热为191.63J/g,热导率大约是纯SAL[0.248W/(m·K)]的47.5倍。而红外成像结果则验证了复合PCMs的瞬态温度变化与其热导率密切相关。

A stearyl alcohol/Co_(3)O_(4)/expanded graphite(SAL/Co_(3)O_(4)/EG-P) composite phase change material(PCMs) was prepared by melt blending-extrusion molding using stearyl alcohol(SAL) as phase change material, Co_(3)O_(4)/EG as supporting material, respectively. The introduction of EG was used to improve the thermal conductivity of PCM, and the PCMs was chemically modified by Co_(3)O_(4). The structure of Co_(3)O_(4)/EG-P was observed by SEM. The result showed that the prepared Co_(3)O_(4)/EG-P exhibited a three-dimensional coupled network and a hierarchical porous structure. EG could effectively prevent the structural collapse and aggregation of metal-organic framework derivatives. The morphology and thermal properties of composite PCMs were characterized by SEM, DSC and infrared imager. As the mass ratio of Co_(3)O_(4) to EG increased from 1∶1 to 1∶8, the thermal conductivity of composite PCMs displayed an increasing trend. When m(Co_(3)O_(4))∶m(EG)=1∶8, the sample had a melting temperature of 51.26 ℃ and a latent heat of 191.63 J/g, and the thermal conductivity of PCMs was about 47.5-fold that of pure SAL [0.248 W/(m·K)]. The infrared imaging results verified that the transient temperature variation of the composite PCMs was closely related to its thermal conductivity.