Influence of maleic anhydride grafting on the rheological properties of polyethylene terephthalate–styrene butadiene blends

The rheological properties of polyethylene terephthalate (PET)–styrene butadiene rubber (SBR) blends are studied in this work. The shear viscosity was measured in a special capillary device mounted on an injection-molding machine, which provides data on pressure and flow rate. Comparison of the viscosity of the PET–SBR physical blend with that of the blend of PET with maleic anhydride-functionalized SBR (SBRg) provides information on the effect of grafted maleic anhydride chains at the rubber–thermoplastic interface on the rheological properties of the blend. Shear viscosity is a function of the amount of compatibilizer and applied shear stress present in the preparation of the blends. A reduction in the particle size due to increasing screw speed was correlated with a reduction in the shear viscosity and an increase in the impact properties of the blend.