为了研究热老化对聚丙烯聚集态结构的影响，采用熔融共混和接枝改性方式分别制备了两种聚丙烯绝缘料，对各试样进行了加速热老化试验，并通过X射线衍射、差示扫描量热法、偏光显微镜对热老化前后试样的聚集态结构进行表征。结果表明：老化前的共混型聚丙烯仅存在α晶体，热老化可使其诱导产生β晶体，而接枝型聚丙烯老化前后均为α晶体和β晶体共存，但老化后β晶体含量出现明显下降。两种聚丙烯的结晶速率均较交联聚乙烯（XLPE）高。其中，接枝型聚丙烯具有明显的异相成核作用，其晶体更加完善且晶体尺寸分布均匀，结晶度高达40.17%。同时，在热老化过程中，接枝型聚丙烯试样表现出较优的抗热氧老化能力，受损程度明显低于共混型聚丙烯试样。

In order to investigate the effect of thermal aging on the aggregation structure of polypropylene, two kinds of polypropylene insulating materials were prepared by melt blending and grafting modifications, and accelerated thermal aging tests were carried out on each specimen. The structures of the aggregated states before and after thermal aging were characterized by X-ray diffraction, differential scanning calorimetry, and polarizing optical microscopy. The results show that only α-crystals exist in the blended polypropylene before aging, and thermal aging can induce the production of β-crystals, while the αcrystals and β crystals coexist in the grafted polypropylene before and after aging, but β crystal content decreases significantly after aging. The crystallization rate of the two polypropylene is significantly higher than that of cross-linked polyethyline (XLPE), in which the grafted polypropylene has obvious heterophase nucleation, its crystal is more perfect and the crystal size distribution is uniform, and the crystallinity is as high as 40.17%. At the same time, grafted polypropylene specimens show better resistance to thermal oxygen aging, and the damage degree of grafted polypropylene specimens is significantly lower than that of blended polypropylene specimens.