A rheo-optical study of shear-thickening and structure formation in polymer solutions. Part I: Experimental

摘要: Simultaneous measurements of the optical and theological response solutions highly fractionated polystyrenes have been made, in-situ, to ascertain connection between flow-induced structure formation phenomenon shear-thickening. Transient steady state viscosity, dichroism, birefringence associated orientation angles were measured in decalin bromobenzene semi-dilute region using a couette device capable shear rates up 8,000 s−1. A one-to-one correlation has found occurrence maxima dichroism minima viscosity. While size shape shear-thickening structures could not be directly determined, results suggest they are intermediate cluster entangled chains completely phase-separated liquid. For exhibiting shear-thinning alone, no maximum was observed, signal instead showed saturation behavior at high rates. Birefringence insensitive attributable that dissolved or entanglement regions. The kinetics structuring process leading instantaneous reversible there is concentration window, above below which only occurs.