Enhanced multiphase interfacial interaction of impact polypropylene copolymer by in-situ introducing polyethylene

Impact polypropylene copolymer (IPC) is utilized in various commercial products worldwide due to its excellent physical properties and low production costs. Introducing polyethylene (PE) into IPC is known to improve the impact properties with little rigidity loss, but little is known about the influence of the multiphase interfacial interaction on these properties. In this work, we investigate this matter through fabricating a series of in-reactor alloys with multi-stage polymerization. Morphology observations revealed that introducing PE into IPC in-situ can promote the phase structure without the external force. Dynamic mechanical analysis results revealed that the introduction of well-dispersed PE in-situ could strengthen the interface interaction between PP matrix and EPR dispersed phase, which is conducive to the dissipation of impact energy. Atomic force microscopy-infrared results suggested that the in-situ introduction of PE promotes the enrichment of the ethylene-propylene block copolymers (EbP) to the multiphase interface. This work offered a new insight into the rational design of the next generation IPC with improved properties.