Investigation of rheological behavior of polyamide 6/acrylonitrile-butadiene-styrene/nanoclay in transient shear flow

Linear and nonlinear (in both steady and transient shear flows) rheological properties of polyamide 6/acrylonitrile-butadiene-styrene (PA6/ABS) nanocomposite blends have been investigated. Characterization of nanocomposite samples morphology by scanning electron microscopy revealed that with increasing nanoclay loading, size of dispersing phase droplets decreases significantly and their uniformity improved considerably. Transmission electron microscopy observations clearly display a coexistence of intercalate and exfoliate structure for nanoclay in the polymer-blend nanocomposite. On the other hand, we see that the tactoids are collected of a few silicate layers and possibly also of a single silicate. In other words, the results on rheological properties indicated that overshoots were observed for the start-up tests after different shear rates and delay times. Also, the results showed that the height of these overshoots increased with the applied shear rate and delay time. In addition, the overshoots are highly dependent on the network structure of the blends, and the magnitude of the overshoots increases with increasing nanoclay content. Hence, at very short delay time, the transient shear viscosity does not display any overshoot, while with increment in the delay time, the overshoot appears and increases as the delay time increases. Presented results revealed that increment in the preshearing rate decreases elastic and increases viscose behavior of nanocomposite samples.