正辛酸-肉豆蔻酸低温相变材料的制备和循环性能

Preparation and cyclic properties of low temperature phase change materials of n-caprylic acid and myristic acid

研制了一种用于相变温度在2~8℃的医药冷藏运输系统的二元有机复合相变材料,该材料由正辛酸与肉豆蔻酸按比例混合而成。首先通过理论计算预测二元混合物的共晶点,确定它的低共熔混合物的比例、相变温度以及潜热值,然后围绕共晶点比例配制了6种不同比例的混合物。使用步冷曲线法测得正辛酸与肉豆蔻酸的低共熔点温度为6.2℃,过冷度为0.5℃,其质量比为87∶13。经过差示扫描量热仪(DSC)测得复合相变材料的相变温度为7.13℃,相变潜热为146.1J/g,热导率为0.2832W/(m·K)。对正辛酸-肉豆蔻酸复合相变材料进行40次、80次的循环充放冷实验,发现其相变温度和潜热值均未发生明显变化。实验结果表明,该材料在蓄冷系统尤其是医药冷藏运输系统中有着很大的应用潜力。

This paper developed a binary organic composite phase change material that is used for pharmaceutical refrigerating transportation system with the phase change temperature of 2—8℃. The material was mixed with a mixture of n-caprylic acid and myristic acid. First two binary eutectic points were determined through the theoretical calculation method to calculate the eutectic mixture ratio, phase transition temperature and latent heat value. Then six different proportion of mixtures around the eutectic point were made. The low melting point temperature of n-caprylic acid and myristic acid was found to be 6.2℃,the sub-cooled temperature by 0.5℃. The mass ratio was found to be 87∶13. The phase transition temperature of the composite phase change materials was 7.13℃ and the latent heat of phase change measured by differential scanning calorimeter（DSC）was found to be 146.1 J/g. The thermal conductivity of eutectic liquid was measured by Hot Disk and was found to be 0.232 W/（m·K）. It was found that the phase transition temperature and latent heat value of the composite phase change materials of n-caprylic acid and myristic acid were 40 times and 80 times more respectively. However,it was found that the phase change temperature and latent heat value were not altered. The results showed that the composite had great potential in the cold storage system,especially in medicine cold storage transportation system.