Fabrication and toughening mechanism of high toughness PP/SEBS/HDPE blends with core-shell particles

Aiming at obtaining high toughness polypropylene (PP) products, in this work, using high density polyethylene (HDPE) and styrene-ethylene-butylene-stryrene (SEBS) as toughening agents, PP/SEBS/HDPE blends were successfully fabricated by melt-blending method, and the microstructure, mechanical, thermodynamics, and rheological properties of the blends were investigated. The results revealed the core-shell structure particles with HDPE as the core and SEBS as the shell were dispersed in PP in the PP/SEBS/HDPE blends. The core-shell structure particles played good roles in toughening PP matrix, and the PP/SEBS/HDPE blends underwent brittle-tough transition at 15 wt% SEBS and 5 wt% HDPE. The impact toughness of PP/SEBS/HDPE blends with 15 wt% SEBS and 15 wt% HDPE reached 60.1 kJ/m², which was almost 1441.0% that of pure PP. The formation of core-shell particles in the system led to an increase in the degree of chain entanglement between the dispersed phase and PP, which enhanced the interfacial adhesion. In addition, based on the experimental results, the relationship between the viscosity and the material toughness was proposed, revealing the brittle-ductile transition behavior and the toughening mechanism.