dsc测量比热容教学文案.ppt

New proposed methodology for specific heat capacity determination of materials ; Abstract; abstract; 一、introduction;TES technologies sensible heat storage the process by which the heat is accumulated due to the increase of the material temperature without experimenting structural changes, no phase change latent heat storage phase change , thermochemical energy material selection A high storage capacity Therefore,need a high specific heat capacity. ;定义：在程序控制温度下，测量物质与参比物之间的能量差随温度变化关系的一种技术。 DSC曲线峰包围的面积正比于热焓??变化 可以测定多种热力学和动力学参数，例如比热容、反应热、转变热、相图、反应速率、结晶速率、高聚物结晶度、样品纯度等。该法使用温度范围宽（-175~725℃）、分辨率高、试样用量少。适用于无机物、有机化合物及药物分析。; 采用试样和一标准物质在相同条件下进行扫描，然后量出二者的纵坐标进行计算。要求标准物质在所测温度范围内没有发生物理化学变化，且比热容已知。常用的标准物质是蓝宝石。具体作法是在DSC内先用两个空样品皿，以一定的升温速度作一条基线，然后放入蓝宝石样品在相同条件下作一条DSC曲线，最后在同样条件下作未知试样的DSC曲线，如图;three DSC methods for Cp measurement The dynamic method has traditionally been used to measure PCM latent heat but also for Cp measurements applying high heating rates in the temperature range of study The areas method is based on the Cp value, thus, how much heat flux is needed to heat up a material for temperature increase, and consists of consecutive isothermal stages differing 1 ℃ with no heating segments amid The isostep method is an intermediate between these two, as it is a succession of dynamic methods applied to heat up the material just 1 ℃ between isothermal segments. This method has been tested in glass transition pharmaceutical studies with good results obtained , but it has not been used for TES materials Cp determination, thereby its selection for this study ;二、Materials; determined by differential scanning calorimetry (DSC) Standard 40 uL aluminium crucibles weigh with a analytical balance with a precision of 0.01 mg. The procedure to determine the specific heat capacity of a material consists of three different measurements, all done under the same conditions, thus, using the same DSC method: Blank measurement. It is necessary to run an experiment with an em