3.3.4 DSC
The melt-crystallization behavior of the polymer is determined by DSC. Figure 8 is represented the DSC curves of PP and SCG/PP composites. It can be seen from the melting curve (a) that the melting peak moves to low temperatures at different degrees, which is the result of the dilution effect caused by the addition of filler. In addition, the crystallinity of PP decreased after the addition of SCG, because the regularity of PP molecular chain was destroyed by the addition of filler SCG. In addition, the cross-linking effect between the two restricts the movement of polymer molecular chain, and the crystal growth of PP is restricted, thus reducing the crystallization ability. The crystallization curve (b) shows all the crystallization peaks are single exothermic peaks, indicating that SCG does not affect the crystal type of PP. During the cooling process, the crystallization peak moved slightly to a high temperature after the addition of SCG, and the degree of undercooling decreased, indicating that SCG played a role in promoting heterogeneous nucleation and making PP crystallize at a higher temperature. Table 2 is the data table of DSC test results.