Synergistic toughening of polypropylene using recycled PVB and POE-g-MA via one-step reactive blending

In this study, recycled poly(vinyl butyral) (r-PVB) and maleic anhydride grafted poly(ethylene-octene) (POE-g-MA) were employed to synergistically toughen polypropylene (PP) via one-step reactive melt blending. Results revealed that hydroxyl groups of r-PVB reacted with anhydride groups of POE-g-MA at the interface, generating in situ compatibilizers and significantly improving interfacial adhesion. Although thermodynamic predictions suggested that POE-g-MA should encapsulate r-PVB, the actual morphology was dominated by viscosity-driven kinetics, leading to the formation of a unique core-shell structure with r-PVB as the shell and POE-g-MA as the core. This morphology effectively promoted energy dissipation, enabling the PP/r-PVB/POE-g-MA (70/10/20) blend to achieve a notched impact strength of 78.0 kJ/m 2 , which is 16.6 times higher than that of neat PP, thus realizing super-toughening. This work not only provides a new pathway for value-added recycling of r-PVB but also reveals a kinetic-dominated mechanism of phase morphology in reactive multicomponent blends.