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采用微量量热法 ,利用Calvet低温微量量热计对Na2 SO4·10H2 O共晶相变畜冷材料进行热化学研究的工作。在不同实验条件下 ,本研究测定出材料的相变热为 118 19J/ g ,固体平均比热容为 5 5 6J/gK-1,液体平均比热容为 14 38J/ gK。测试结果还表明 ,随着悬浮剂的加入 ,材料的相变热增大 ;所测得的升温DSC曲线的相变热略高于降温过程的相变热 ,本研究还测得了材料 4 5℃ ,5 5℃ ,6 5℃和 7 5℃下的等温DSC数据。以Avrami方程作数据处理的结果表明 ,该方程可以良好地描述该体系的结晶过程。温度的降低 ,成核剂适量加入 ,都将导致Avrami方程速率常数逐渐增大。数据处理解得过程的活化能为 95 3 6kJ/mol,数值为 2 32～ 2 4 3的Avrami方程时间指数表明该体系的结晶过程应为三维依热成核机理 ,显微照相的图象结果亦证实了这一结论。本研究表明了以微量量热法进行新型的相变蓄冷材料的研究与开发的有效性
Calculus calorimetry was used to study the thermochemistry of Na2 SO4 · 10H2 O eutectic phase change animal feedstock by Calvet low temperature microcalorimeter. Under different experimental conditions, the phase transition heat of the material was 118 19 J / g, the average specific heat capacity of the solid was 556 J / gK-1, and the average specific heat capacity of the liquid was 14 38 J / gK. The results also show that with the addition of SC, the phase transition heat of the material increases. The phase transition heat of the DSC curve is slightly higher than that of the cooling process. In this study, , Isothermal DSC data at 55 ° C, 65 ° C and 75 ° C. The results of data processing with Avrami equation show that this equation can well describe the crystallization process of this system. The decrease of temperature and the proper amount of nucleating agent will lead to the increasing of the rate constant of Avrami equation. The time-index of Avrami equation with activation energy of 95 3 6 kJ / mol and data of 2 32 ~ 2 4 3 in the data processing and interpretation process indicates that the crystallization process of the system should be three-dimensional according to the thermal nucleation mechanism and the result of photomicrography Also confirmed this conclusion. This study shows the effectiveness of the research and development of new phase change cold storage materials by the microcalorimetry method