改性氧化铜/正十八烷复合相变材料制备及性能表征研究

Preparation and characterization of modified CuO nanoparticles/n-octadecane phase change material

为了提高复合相变材料的稳定性及热物性,采用油酸钠(SOA)对氧化铜纳米颗粒(CuO)进行改性处理,获得了改性纳米颗粒M-CuO,并制备了不同M-CuO含量的正十八烷复合相变材料(CPCM)。实验结果表明,当添加3.0%的M-CuO纳米颗粒时,复合相变材料的导热系数比正十八烷提高282.9%。而M-CuO的质量分数为2.0%时,熔化焓最多降低6.3%。为进一步提高纳米颗粒的分散稳定性,向复合相变材料中添加油酸钠作为表面活性剂。研究发现与无表面活性剂相比,复合相变材料导热系数进一步提高10.4%。最后,采用分子动力学方法建立了M-CuO/正十八烷复合相变材料模型,计算结果表明在不同纳米颗粒间距下(20Å、30Å和40Å),相比于添加CuO纳米颗粒,添加M-CuO纳米颗粒的复合相变材料导热系数分别提高了8.6%、10.4%和11.2%,且M-CuO纳米颗粒之间的相互作用能分别降低了22.9 kcal/mol、16.3 kcal/mol和20.0 kcal/mol,对CuO纳米颗粒进行改性处理能有效降低其相互作用能,增强其稳定性。本研究为纳米复合相变材料的性能强化和优化提出了重要的理论指导,并揭示了微观机制。

To enhance the stability and thermophysical properties of composite phase change materials(CPCM),sodium oleate(SOA)was employed to modify CuO nanoparticles,integrating them with n-octadecane to formulate PCMs at varying modified nanoparticle(MCuO)concentrations.The experimental outcomes indicated a significant increase in the thermal conductivity of CPCM containing 3.0% M-CuO—up to 282.9% compared to pure noctadecane.Additionally,the melting enthalpy decreased by as much as 6.3% with an M-CuO content of 2.0%.To further enhance the dispersion stability of the nanoparticles,sodium oleate was incorporated as a surfactant,resulting in a thermal conductivity increment of 10.4%for the CPCM compared to those without the surfactant.Molecular dynamics modeling of M-CuO/n-octadecane CPCM revealed that the thermal conductivity was enhanced by 8.6%,10.4%,and 11.2% at nanoparticle distances of 20Å,30Å,and 40Å,respectively.Moreover,the interaction energies between M-CuO nanoparticles were reduced by 22.9,16.3,and 20.0 kcal/mol,respectively,indicating a reduction in interaction energy and an enhancement in their stability.This study provides critical theoretical insights into the thermophysical property enhancement and optimization of CPCM,uncovering the fundamental microscopic mechanisms involved.