Preparation, non-isothermal crystallization, and melting behavior of β-nucleated isotactic polypropylene/poly (ethylene terephthalate) blends

β-nucleated PP/PET blends were prepared using nano-CaCO3 supported β-nucleating agent (β-NA), PP as matrix, and PET as dispersion phase. The effects of preparation methods, PET content, and melting temperature on the non-isothermal crystallization behavior and the melting characteristic and polymorphic composition of PP in the blends were investigated by differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD). The results indicated that the PP crystallized predominantly in β-modification in the presence of β-NA. However, efficiency of β-NA for PP crystallization decreased with addition of PET and increasing PET contents. The β-nucleation of β-NA for PP crystallization in the blends was dependant on the preparation methods. The high β-nucleation and high β-PP content were obtained for PP/PET blend prepared at the temperature of 265 °C and added the β-NA into the blend at the temperature of 180 °C. However, the addition of β-PP or β-NA into blends at 265 °C decreased the β-nucleation, and no β-PP was formed because the β-NA mainly dispersed on the PET dispersion phase or at the interface between PP and PET.