差示扫描量热法测定费托蜡滴熔点的研究

Research on determination of drop melting point of Fischer-Tropsch wax by differential scanning calorimetry method

采用DSC法对费托蜡滴熔点进行测定,研究了升降温速率、升温次数、起始和终止温度、氮气吹扫气流量、平衡时间、试样质量等对测试结果的影响,确定了DSC法测定滴熔点的适宜条件,考察了DSC法测定费托蜡滴熔点的重复性、准确性和再现性。实验结果表明,DSC法测定费托蜡滴熔点的适宜条件为:第一次升降温速率20℃/min、第二次升温速率5℃/min、熔融过程的起始温度为室温、终止温度高于预估滴熔点20~30℃、取样质量5~10 mg、氮气吹扫气流量10~50 mL/min、熔融与结晶过程转变平衡时间2 min。DSC法测定费托蜡滴熔点操作简单、试样用量少、检测速率快、重复性和再现性良好、测试结果准确,可作为传统方法的替代手段。

The DSC method was used to determine the drop melting point of Fischer-Tropsum wax.The effects of heating and cooling rate,heating frequency,starting and ending temperature,nitrogen purge gas flow rate,equilibrium time,and sample mass on the test results were studied.The suitable conditions for determining the drop melting point by DSC method were determined,and the repeatability,accuracy,and reproducibility of DSC method were investigated.The experimental results show that the suitable determination conditions are as follows:the first heating and cooling rate is 20℃/min,the second heating rate is 5℃/min,the starting temperature of the melting process is room temperature,the ending temperature is 20-30℃higher than the expected drop melting point,the sampling mass is 5-10 mg,the nitrogen purge gas flow rate is 10-50 mL/min,and the transition equilibrium time between melting and crystallization process is 2 min.With the advantages of simple operation,small sample mass,fast detection rate,good repeatability and reproducibility,and accurate test results,the DSC method can be used as an alternative to traditional methods for determining the drop melting point of Fischer-Tropsum wax.