铜纳米粒子导热增强固-液相变储能材料的性能

Properties of solid-liquid phase change materials based on copper nanoaggregates with enhanced thermal conductivity for storing thermal energy

使用聚乙烯吡咯烷酮(PVP)和聚乙二醇(PEG)作为钝化剂对铜纳米颗粒进行原位包覆制备了PVP/PEG/Cu复合纳米粒子(CuNP),将其作为导热增强剂引入到PEG中制备了CuNP/PEG固-液相变储能材料(PCMs),并通过FTIR、XRD、DSC以及TGA表征了CuNP/PEG固-液PCMs的结构及热性能。利用纳米粒子表面的PVP与PEG之间的氢键和空间位阻效应,以及PVP对铜核的保护作用,赋予了铜纳米粒子在PCMs中优异的分散稳定性。结果表明,CuNP的引入能够显著提高复合相变储能材料的导热能力,并能够作为晶核加速材料的结晶行为。当纳米粒子的质量分数为5%时,CuNP/PEG固-液PCMs的相变焓为157.0 J/g,体系的储热速率、放热速率和结晶速率与纯PEG相比分别提高了34.09%、31.45%和53.33%。

CuNP/PEG solid-liquid phase change materials(PCMs) were synthesized via introduction of thermal conductivity enhancer PVP/PEG/Cu composite nanoaggregates(CuNP), which was prepared by in-situ coating copper nanoparticles with passivators of polyvinyl pyrrolidone(PVP) and polyethylene glycol(PEG), into polyethylene glycol, and then characterized by FTIR, XRD, DSC and TGA for analyses of structural and thermal properties. Excellent dispersion stability of copper nanoparticles in PCMs were obtained because of the hydrogen bond and steric hindrance between PVP and PEG on the surface of the nanoparticles and the protective effect of PVP on copper core. The results showed that Cu NP significantly improved the thermal conductivity of the PCMs and acted as crystal nucleus accelerating the crystallization behavior of the material. When the mass fraction of CuNP was 5%, the phase change enthalpy of the CuNP/PEG PCMs was 157.0 J/g. Moreover, in comparison to those of pure PEG, the heat accumulation rate, heat release rate, and crystallization rate were increased 34.09%, 31.45% and 53.33%, respectively.