Effect of shear history on rheological

MOLDENAERSETAL. Effect of Shear History on Rheological Behavior... 

Prud homme, R. K., Constien, V., and Knoll, S. (1989). The effects of shear history on the rheology of hydroxypropyl guar gels. In Polymers in Aqueous Media, Glass, J. E. (Ed.), Advances in Chemistry 223, pp. 90-112. Am. Chem. Soc., Washington, DC. 

The Effects of Shear History on the Rheology of Hydroxypropyl Guar Gels... 

Figure 4.5 The effect of shear histories on the flow properties of titanium dioxide (TiOa) water 27.7% suspensions stabilized with 5mg/g Ti02 of Na4P2O7-10H2O. (Reprinted from Ref. 142 with kind permission from Society of Rheology, USA.)...

Marrucci G, Maffettone PL (1993) Liquid crystalline polymers. Pergamon, New York Mead DW (1994) Determination of molecular weight distributions of linear flexible polymers from linear viscoelastic material functions. J Rheol 38 1797-1827 Moldenaers P, Yanase H, Mewis J (1990) Effect of shear history on the theological behavior of lyotropic liquid crystals. Liq Cryst Polym 24(1990) 370-380 Muir MC, Porter RS (1989) Processing rheology of liquid taystal polymers a review. Mol Cryst Liq Cryst 169 83-95... 

EFFECT OF MULTIPLE SHEAR HISTORIES ON RHEOLOGICAL BEHAVIOR AND DEVOLATILIZATION OF POLY(ETHER ETHER KETONE)... 

More recently, a closer inspection of the transient stress rheology for thickening systems has revealed more complicated patterns, such as structural memory effects. Berret et al. [78] and Oeschlager et al. [93,107] have observed that the transient mechanical response also depended on the thermal and shear histories. Samples having been treated thermally, e.g., heated up to 90 °C for 2h, behaved very differently from samples freshly prepared or already sheared. The induction time couid last several hours, and was not proportional to the inverse shear rate, as mentioned previously. It was concluded that the lack of reproducibility under certain thermal and shear conditions might indicate that these surfactant solutions were characterized by long-lived metastable states. 

We have shown in the preceding section that the rheological properties of particulate-filled molten thermoplastics and elastomers depend on many factors (1) particle size (t/p), (2) particle shape (a), (3) volume fraction of filler (f)), and (4) applied shear rate (y) or shear stress a). The situation becomes more complicated when interactions exist between the particulates and polymer matrix. There is a long history for the development of a theory to predict the rheological properties of dilute suspensions, concentrated suspensions, and particulate-filled viscoelastic polymeric fluids. As early as 1906, before viscoelastic polymeric fluids were known to the scientific community, Einstein (1906,1911) developed a theory predicting the viscosity of a dilute suspension of rigid spheres and obtained the following expression for the bulk (effective) viscosity of a suspension ... 

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