月桂酸/膨胀珍珠岩复合相变材料的制备与热性能研究

以月桂酸为相变材料,膨胀珍珠岩为载质,利用真空吸附法制备出月桂酸/膨胀珍珠岩复合相变材料(LA/EP-PCMs)。通过FT-IR、SEM、DSC、TGA对LA/EP-PCMs的微观结构、相变温度、相变潜热、热稳定性进行表征。结果表明:月桂酸能较好地吸附在膨胀珍珠岩孔隙内,它们之间的化学相容性良好。LA/EP-PCMs中月桂酸饱和含量为65%,此时其相变温度为41.3℃,热焓为110.1J/g。将5%的纳米石墨纤维(NGF)作为添加剂加入到LA/EP-PCMs中,其导热系数由0.09 W/(m·K)提高到0.16 W/(m·K),增长了77.7%。熔融凝固实验表明:掺入NGF将改善复合相变材料的蓄放热能力,其强化导热机理是在相变基体外表面和内部形成了导热网络。

Preparation of Lauric Acid/Expanded Perlite Composite Phase Material and Its Thermal Performance

Lauric acid/expanded perlite phase change materials(LA/EP-PCMs) were prepared by vacuum absorption method with lauric acid as phase change materials,expanded perlite as skeleton.The microstructure,phase change temperature,latent heat as well as thermal stability of LA/EP-PCMs were investigated by FT-IR,SEM,DSC and TGA,respectively.The results showed that lauric acid could be absorbed in the pore of porous expanded perlite well and had good chemical compatibilities with expanded perlite.As the saturated mass fraction of lauric acid of LA/EP-PCMs is 65％,phase change temperature and latent heat of the phase change materials were determined as 41.3 ℃ and 110.1 J/g.The thermal conductivity was increased from 0.09 W/(m · K) to 0.16 W/(m · K),which was increased by 77.7％ when 5％ nano graphite fiber (NGF) was added into LA/EP-PCMs as additive.Experiment of melting and frozen showed that the incorporation of NGF improved the thermal release capacity of composite phase change materials,and the thermal conduction mechanism was the formation of thermal conduction network on the outer and inner surfaces of the phase change substrate.