Realizing simultaneous reinforcement and toughening in polypropylene based on polypropylene/elastomer via control of the crystalline structure and dispersed phase morphology

In this work, an advanced extrusion approach (MSEDC technique) was adopted to control crystalline structure and phase morphology in PP/POE blends. The results showed that PP matrix alternating shish-kebab crystalline structure with spherulites, and POE phase alternating micro-/nano-sheets with nanofibrils and elongated spherical particles were introduced into PP/POE blends simultaneously. The as-obtained densely-stacked shish-kebab crystalline structure of the PP matrix can provide blends with greatly enhanced tensile yield strength, while the planar POE phase with micro-/nano-sheets can induce the deflection of crack, providing the blends with greatly increased toughness. Moreover, hierarchical interfacial entanglement, formed between PP molecules and POE molecules, can connect the matrix and dispersed phase effectively, which is helpful to obtain materials with simultaneously enhanced strength and toughness. Compared with neat PP, the notched impact strength and tensile yield strength of MSEDC PP/POE blends is enhanced 490% and 35%, respectively, which is the first report realizing simultaneous reinforcement and toughening in polypropylene based on a polypropylene/elastomer binary system.