Melt rheology of compatibilized polystyrene/low density polyethylene blends

Investigations have been made on the melt rheological behaviors of compatibilized blends composed of polystyrene, low density polyethylene and hydrogenated (styrene‐butadiene‐styrene) triblock copolymer used as a compatibilizer. The experiments were carried out on a capillary rheometer. The effects of shear stress, temperature and blending ratio on the activation energy for viscous flow and melt viscosity of the blends are described. The study shows that the viscosity of the blends exhibits a maximum or minimum value at a certain blending ratio. The activation energy for viscous flow decreases with increasing LDPE content. Furthermore, the concept of equal‐viscosity temperature is presented and its role in the processing of the blend is discussed. In addition, the morphology of the extrudate sample of the blends was observed by scanning electron microscopy and the correlation between the morphology and the rheological properties is explored. © 1999 Society of Chemical Industry