Effects of modified kaolin on the crystallization property of PP/Kaolin nanocomposites

Modified kaolin-filled polypropylene was prepared by blending different kinds of modified kaolin intercalated master batches with polypropylene. The microstructure of PP/ Kaolin was studied with X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) photos. The effects of the organic kaolin master batches on the crystallization property of polypropylene were investigated by means of non-isothermal differential scanning calorimetry analysis (DSC) and polarized light microscopy (PLM). Non-isothermal crystallization kinetics of polypropylene was studied by the use of modified Avrami Equation improved by Jeziorny. The results indicate that some organic kaolin can be exfoliated by polypropylene, proved by an invisible 001 peak on XRD pattern and individual layer on transmission electron microscopy (TEM) photos, and the heterogeneous nucleus increased with the addition of modified kaolin, proved by the PLM photos. The filled polypropylene crystallizes fastest at 395 K. The results also show that organic kaolin master batches not only can effectively accelerate the heterogeneous nucleation of polypropylene but also can increase the rate of crystallizing point and the temperature of crystallization. However, the rate constant of crystallization remains unchanged.