Determination of Melting and Crystallization Temperatures by DTA or DSC

From the melting endothermic peak and the crystallization exothermic peak of DTA or DSC curves, transition temperatures can be determined. In order to erase the effect of the previous thermal history, such as superheating, super- 

Before the measurement, maintain the sample at a temperature of 23 2 C and a relative humidity of 50 5% for more than 24 h for conditioning. 

Weigh about 10 mg of the sample with a precision of 0.1 mg. If the sample contains a large amount of the additive, 5-10 mg of pure sample (e.g. polymer) is sufficient. Since milligram quantities of sample are used, it is essential to ensure that the samples are homogeneous and representative. 

Place the conditioned sample into the pan of a DSC or DTA instrument. Heat the sample from ambient up to 30 C above the final temperature of the melting peak and maintain at this temperature for 10 min to ensure melting of the sample. Subsequently cool to at least 50 C below the final temperature of crystallization. 

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