正辛酸-癸酸/膨胀石墨低温复合相变材料的制备及热物性研究

Preparation and thermophysical property of low temperature composite phase change material OA-CA/EG

针对有机相变材料热导率低的问题,以质量比71∶29的正辛酸(OA)-癸酸(CA)为基液,通过添加膨胀石墨(EG)制备用于医药冷藏运输系统的复合相变材料。利用EG表面多孔结构的吸附性原理,制备出EG最佳质量分数为8%的OA-CA/EG低温复合相变材料。通过差示扫描量热仪测得OA-CA/EG的相变温度为0.9℃,相变潜热为112.7J/g。利用热常数分析仪测得OA-CA的热导率为0.3231W/(m·K),OA-CA/EG的热导率为1.649W/(m·K),加入EG使得OA-CA的热导率提高了4.1倍。对OA-CA/EG进行100次蓄放冷循环实验,结果表明循环前后其相变温度、潜热值以及热导率均未发生明显变化。稳定的蓄放热性能使得OA-CA/EG在医药冷藏运输系统具有广阔的应用前景。

In view of the low thermal conductivity of organic phase change materials,a mass ratio of 71∶29 octanoic acid(OA)and cauric acid(CA)as a base fluid was developed by adding the expanded graphite(EG)to enhance the thermal conductivity,which can be used in refrigerated transport system for medicine.The OA-CA/EG low temperature composite phase change material with the optimal ratio of EG was 8wt%was prepared based on the adsorption principle of porous structure on EG surface.The transition temperature and the latent heat were measured by differential scanning calorimetry(DSC).The results showed that the phase transition temperature of the solution was 0.9℃and the latent heat of phase change was 112.7J/g.The thermal conductivity of OA-CA/EG was 1.649W/(m·K)measured by hot disk thermal constant analyzer,which was 4.1 times higher than that of OA-CA,0.3231W/(m·K).The freeze-thaw cycle test of OA-CA/EG was carried out for 100 times and there was no significant change in the phase change temperature,latent heat value and thermal conductivity.Therefore,this material had great prospect in the practical application to medical refrigeration transportation system.