The degree of crystallinity of a sample can be determined from its DSC heating curve by calculating the enthalpy of fusion (Hm) and comparing it to the enthalpy of fusion of a 100% crystalline sample (Hm0). The degree of crystallinity is then calculated using the following equation:

Degree of crystallinity (%) = Hm / Hm0 * 100%

The enthalpy of fusion is calculated by integrating the area under the melting peak on the DSC heating curve. In the heating curve you provided, the melting peak is the sharp peak at around 165°C. To calculate the enthalpy of fusion, you would need to integrate the area under this peak from the onset to the end of melting.

Is your area correct?

It is difficult to say for sure whether your area is correct without seeing the entire DSC heating curve. However, based on the image you provided, it appears that you have integrated the area under the melting peak correctly.

Should you consider the peak before the melting peak?

The peak before the melting peak is likely due to cold crystallization. Cold crystallization is a process where polymer chains that have not crystallized during cooling crystallize during heating. The enthalpy of cold crystallization is typically much smaller than the enthalpy of melting. Therefore, you can usually ignore the peak before the melting peak when calculating the degree of crystallinity.

Is this an example of cold crystallization?

Yes, the peak before the melting peak in your DSC heating curve is likely due to cold crystallization.

Overall, I think you are on the right track to calculate the degree of crystallinity of your sample. To get the most accurate results, you should integrate the area under the melting peak from the onset to the end of melting using a DSC data analysis software.

Good luck