A correlation between rheology and morphology of polypropylene/poly(trimethylene terephthalate) blend nanocomposites was addressed. Organoclay particles were preferentially localized either at the interface or inside the polyester phase depending upon affinity the level and exerted compatibilizing role by making a finer morphology. The functional compatibilizer was found to be highly efficient in giving rise to an enhanced interfacial adhesion and uniform morphology. The compatibilizer also expanded the clay gallery space by increasing its interlayer distance. Rheological measurements showed that nanoclay and compatibilizer contribute to the complex viscosity of the system considerably. Also, an upturn was detected at low angular frequencies ascribed to a secondary structure formation. Similar behavior was also found when storage shear modulus was studied, where at low frequencies a terminal plateau of yield stress character appeared that was connected with some intermolecular networks. This was further supported via relaxation time spectra wherein additional peaks due to interface emerged at low frequencies. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013