Effect of β‐nucleating agents on the crystallization behavior and force‐electric properties of the polypropylene blends

Abstract

Polypropylene blends with different crystalline shapes were prepared to explore the effect of crystalline structure on the force and electrical properties of polypropylene‐elastomer blends and the mechanism of influence. The crystallization behaviors of the blends were characterized by x‐ray diffraction (XRD), polarized light microscopy (PLM), and differential scanning calorimetry (DSC). The mechanical and dielectric properties of the blends were tested to find the correspondence between crystallization characteristics and properties. The results show that the addition of the β‐nucleating agent changes the crystalline shape of PP blends from α to β crystalline, significantly reduces the crystallite size of the blends, and significantly improves the crystallinity of the blends by forming dense crystalline regions embedded in each other. The appropriate amount of the β‐nucleating agent facilitates thermal vibration between electrons and lattice and hinders the carrier migration, significantly reducing the conductivity and increasing the breakdown field strength from 84.81 to 102.30 kV/mm.Highlights The β nucleating agents can alleviate the defects of polypropylene's excessive rigidity and effectively improve the mechanical properties of polypropylene blends. Appropriate amount of the β nucleating agent can significantly improve the electrical properties of polypropylene blends. The addition of the β nucleating agent can significantly improve the crystallinity of the blends and construct the dense crystalline region of the interlock. The small size of the crystals improves the breakdown properties of the polymer by increasing the energy exchange between the electrons and the lattice, which mitigates the impact of high‐energy electrons on the polymer.