Ethylene-propylene block copolymer (EbP) is a vital component in impact polypropylene copolymer (IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work, four IPCs were investigated by atomic force microscopy-infrared (AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer (EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

乙烯-丙烯嵌段共聚物（EbP）是抗冲聚丙烯共聚物（IPC）的重要组成部分，但其在多相复合材料中的分布以及它如何影响相结构和机械性能尚不清楚。在这项工作中，通过原子力红外显微镜（AFM-IR）研究了四种IPC，以评估原位相组成，在此基础上结合非原位获得的链微观结构信息，推导出每种IPC的共聚物组分的分布。合金。对于 EbP 包含长 P 和长 E 链段的 IPC，发现 EbP 部分与橡胶和 PP 基质相分离，与 EP 嵌段共聚物 (EsP) 形成分散颗粒的核。相比之下，在具有由长P和短E链段组成的EbP的IPC中，EbP部分形成橡胶颗粒的外壳，其核仅包含EsP，并且该IPC含有比其对应物更低的E共聚单体含量，表现出更好的抗冲击性和更高的弯曲模量。这些结果阐明了 EbP 的链结构如何控制 IPC 中的相形态，进而影响复合材料的性能。