使用稀土类β成核剂WBG-Ⅱ对聚丙烯进行改性，添加质量分数分别为0.1%、0.3%、0.5%、1.0%。结果表明，添加适量的成核剂能够显著改善聚丙烯的结晶特性并提升击穿性能。当成核剂含量达到0.5%时，聚丙烯的结晶度达到54.73%,β晶型含量达到83.7%,击穿场强提升至267.17 kV/mm,均达到峰值。然而，当成核剂含量增至1.0%时，结晶度和β晶型相对含量出现了下降趋势，分别为41.2%和80.7%。同时，击穿场强也有所下降。分析认为，成核剂引发的异相成核是提升了结晶度和β晶型相对含量，同时也增加了微晶间的界面面积，从而增加了平均陷阱密度，提高了载流子被捕获的概率，有效阻碍了空间电荷的注入，最终使介电性能得到了增强。相反，当成核剂过量时，由于团聚效应抑制了异相成核过程，导致结晶度、β晶型相对含量和击穿场强的降低。

The rare earth β nucleating agent WBG-Ⅱ was used to modify Polypropylene, with added mass ratios of 0.1%, 0.3%, 0.5%, 1.0%, respectively. The results show that the addition of nucleating agent significantly improves the crystallinity of Polypropylene and enhances its breakdown characteristics. When the content of nucleating agent reaches 0.5%, the crystallinity of polypropylene reaches 54.73%, the content of β crystal form reaches 83.7%, and the breakdown field strength increases to 267.17 kV/mm, both reaching their peak values. However, when the content of nucleating agent increased to 1.0%, the crystallinity and relative content of β crystal form showed a decreasing trend, dropping to 41.2% and 80.7%, respectively, leading to a decrease in breakdown field strength. Analysis suggests that the heterogeneous nucleation induced by nucleating agents increases crystallinity and relative content of β crystals, while also increasing the interfacial area between micro-crystals, thereby increasing the average trap density, increasing the probability of carrier capture, effectively hindering charge injection, and ultimately enhancing dielectric performance. On the contrary, when the amount of nucleating agent is excessive, the agglomeration effect inhibits the heterogeneous nucleation process, resulting in a decrease in crystallinity, relative content of β crystal form, and breakdown field strength.