癸酸-石蜡/膨胀石墨定形相变材料的制备及性能

通过物理吸附法将癸酸-石蜡（CA-PC）二元低共熔混合物与膨胀石墨（EG）复合形成癸酸-石蜡/膨胀石墨定形相变材料，实验结果显示，CA与PC、CA-PC与EG的最佳质量配比分别为8.1∶1.9和7∶1。利用扫描电子显微镜（SEM）和傅里叶红外光谱仪（FTIR）分析了定形相变材料的微观形貌和结构特点，发现CA-PC/EG的FTIR曲线上同时存在二元低共熔混合物和膨胀石墨的特征吸收峰，表明二元低共熔混合物与膨胀石墨之间没有发生化学反应，二者依靠表面张力和毛细力作用在一起，并且CA-PC二元低共熔混合物依靠物理作用被有效包封于EG的孔隙中，经过1000次加速冷热循环后，基本没有液态二元复合相变材料泄漏。通过差示扫描量热仪（DSC）得到CA-PC/EG的熔化温度和凝固温度分别为27.04℃和22.26℃，熔化潜热和凝固潜热分别为144.4J/g和133.7J/g，且EG的高导热性促进了CA-PC的蓄放热速率。同时，根据热重分析（TG）与蓄放热实验结果发现其拥有优良的热可靠性和耐热性能。因此，该CA-PC/EG定形相变材料是一种良好的低温储能材料。

Preparation and properties of capric acid-paraffin/expanded graphite form-stable phase change materials

Capric acid/paraffin with ceresin (CA-PC) and expanded graphite (EG) were combined to form CA-PC/EG form-stable phase change materials by physical adsorption method. The results revealed that the optimum mass fraction of CA∶PC and CA-PC∶EG were obtained which was 8.1∶1.9 and 7∶1, respectively. The microstructure and characterization of form-stable phase change materials were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FTIR). The characteristic absorption peaks of CA-PC and EG were found to coexist in FTIR curve of CA-PC/EG, indicating that CA-PC and EG were combined by surface tension and capillary forces without chemical reaction. CA-PC binary eutectic mixture was effectively encapsulated in the pores of EG by physical interaction, and there is almost no leakage of liquid binary composite phase change materials after 1000 thermal cycling. The melting and freezing temperatures of CA-PC/EG obtained by differential scanning calorimeter (DSC) were 27.04℃ and 22.26℃, respectively, while the corresponding latent heats were 144.4J/g and 133.7J/g, respectively, The high thermal conductivity of EG promoted the thermal energy storage and release rate of CA-PC. At the same time, according to the results of TG and heat storage experiment, it was found that it had excellent thermal reliability and heat resistance. Therefore, the CA-PC/EG form-stable phase change material was a promising material for applications of low temperature thermal energy storage.