Melt rheological properties of PBT/SEBS and reactively compatibilized PBT/SEBS/SEBS‐ g ‐MA polymer blends

Melt rheological properties of PBT/SEBS and PBT/SEBS/SEBS‐ g ‐MA blends at SEBS volume fraction (Φ d ) = 0.00–0.38 were studied at 240°C, 250°C and 260°C using a capillary rheometer. The compatibilizer SEBS‐ g ‐MA addition resulted in significant reduction in the dynamic interfacial tension which in turn led to increased phase adhesion. The power law exponent n decreased with increasing Φ d and increasing temperature for both the compatiblized and uncompatiblized blends. The consistency index of PBT/SEBS increased with increasing Φ d but were smaller than those of PBT/SEBS/SEBS‐ g ‐MA blends. Melt elasticity such as die swell and first normal stress difference increased with Φ d . Variations of first normal stress coefficient function (ψ 1 ), recoverable shear strain (γ R ), relaxation time (λ), and shear compliance (J c ) values versus shear rate were analyzed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41402.