Rheological Characterization of in situ Compatibilized Binary Polymer Blends With Variable Steady Shear Viscosities of Components

Abstract

Zero shear viscosities of binary polymer blends, η0,bc, of polypropylene (PP)/polystyrene (PS), in situ compatibilized by anhydrous aluminum chloride (AlCl3) catalyst, were obtained by fitting their shear rate sweep curves according to the modified Carreau model. The results showed that the dependence of η0,bc on AlCl3 content was complicated and obviously influenced by viscosity variations of the components as well as the interfacial compatibilization effect of the in situ formed PP-g-PS copolymer. For further investigation, η0,bc was divided into three parts: contribution of the viscosity of components, contribution of phase geometry, and contribution of the interfacial compatibilization effect. The results showed that when the apparent value of the third part was experimentally determined, the significant influence of viscosity variations of the components had to be considered, while the influence of phase morphology geometry resulting from viscosity variations of the components could be ignored experimentally and reasonably within the whole experimental range of AlCl3 content. The contribution of the interfacial compatibilization effect to η0,bc could be used as the rheological parameter to characterize the interfacial character and could be used to interpret the variations of η0,bc of the in situ compatibilized polymer blend successfully. In addition, η0,bc is more sensitive to the shear viscosity variations of the components than the phase structure geometry evolution of the reactive blends.