Effect of silicon nitride nanoparticles on the crystallization behavior of polypropylene

The purpose of this work was to explore in detail the effect of silicon nitride (Si3N4) nanoparticles on the crystallization behavior of isotactic polypropylene (PP). Polarized microscopy, wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry were used to characterize the PP/Si3N4 nanocomposites. The Kissinger and Flynn-Wall-Ozawa methods were adopted for treatment of the crystallization kinetics. The results showed that different contents of Si3N4 nanoparticles would have different effects on the crystallization behavior of PP. Si3N4 nanoparticles at 2wt% could effectively accelerate the nucleation process, while Si3N4 at 5wt% was more favorable in promotion of crystallite growth. Analysis by the isoconversional method of Flynn-Wall-Ozawa confirmed the results obtained by morphology observation and crystallinity (WAXD) analysis. The Kissinger equation was slightly adapted and was used in analyzing the activation energy of nucleation and crystal growth. Satisfactory results were obtained.