FIG. 3 shows the DSC curves of stre

FIG. 3 shows the DSC curves of stretched PVDF and different components of P(vdf-trfe) membrane, and shows the changes of Tc temperature and Tm melting point of the two samples respectively. In the DSC curve, the area of the melting peak is the melting enthalpy of the crystalline part of the polymer, and the higher the crystallinity is, the larger it is. Is the melting enthalpy of polymer at the time of 100% crystallization, and the value of PVDF polymer [18] is 105 J·g-1. The crystallinity (Xc) of the film can be calculated from the calculation formula (1) of crystallinity (Xc).