Mechanically Strong and Ductile Polypropylene/Poly(ethylene-co-octene) Blends Prepared Through Multistretched Extrusion: Morphological Evolution, Toughening, and Reinforcing Mechanism

ABSTRACTIn this paper, polypropylene matrix with densely stacked shish-kebab crystalline structure and dispersed poly(ethylene-co-octene) phase with micro/nanofibers were formed simultaneously in polypropylene/poly(ethylene-co-octene) blends through multistretched extrusion. The as-obtained highly oriented and densely stacked shish-kebab crystalline structure can provide blends with greatly enhanced tensile yield strength. The as-formed poly(ethylene-co-octene) micro/nanofibers can toughen polypropylene matrix effectively through deflecting the crack, which is different from the toughening mechanism in polypropylene/poly(ethylene-co-octene) blends filled with spherical poly(ethylene-co-octene) particles. Compared with that of conventional polypropylene/poly(ethylene-co-octene) blends, the tensile yield strength of multistretched blends increased approximately 300%, while the notched impact strength declined slightly.