Nonlinear rheological properties

Wang, C.F. and Kokini, J.L. (1995). Simulation of the nonlinear rheological properties of gluten using the Wagner eonstitutive model. J. Rheol. 39(6), 1465-1482. 

The concept of polymer entanglements represents intermolecular interaction different from that of coil overlap type interaction. However, it is difficult to define the exact topological character of entanglements. The entanglements concept was aimed at understanding the important nonlinear rheological properties, such as the shear rate dependence of viscosity. However, viscoelastic properties could not be defined quantitatively as is possible with the reptation model. Because an entanglement should be... 

Problem 3.6 exercises your ability to compute nonlinear rheological properties of dilute solutions. 

Sciortino F (2009) Nonlinear rheological properties of dense colloidal dispersions close to a glass transition under steady shear. Adv Polymer Sci. doi 10.1007/12 2009 30... 

The various nonlinear rheological properties (e.g., viscosity ri and normal stress functions and N ) can then be correlated with P. This sort of argument and the basic assumptions of the model have been proven useful, as the model was previously found to fit steady-state data very well (3,4). 

It is demonstrated that MCT generalized in the integration through transient framework provides a full description of the flow curves as well as the viscoelastic behavior of concentrated suspensions with a single set of well-defined parameters, (see Figure 24). The theoretical approach describing nonlinear rheological properties of such dense colloidal suspensions was recently discussed by Fuchs. ... 

Brief Overview of Evolution of Nonlinear Rheological Properties during Polymerization... 

Simultaneous Effects of Mixing, Chemical Reaction, and Molecular Diffusion on the Evolution of Nonlinear Rheological Properties... 

The rate and the extent of conversion in polymerization reactions, the evolution of nonlinear rheological properties, and the formation of polymer networks are closely related to the effectiveness and the type of mixing (chaotic vs nonchaotic)... 

Beside these relaxation experiments, the Giesekus model was also applied for different types of rheological experiments.Up to now, no significant deviations between experimental values and theoretical predictions were detected. The Giesekus model thus gives a successful description of the nonlinear rheological properties of viscoelastic surfactant solutions. This holds for an anisotropy factor a = 0.5. ... 

This model, which was among the very first proposed to explain some aspects of entangled polymers, is mainly aimed at understanding some of the important and dramatic, nonlinear rheological properties, particularly the shear rate dependence of viscosity (Graessley, 1974). The approach was difficult to extend to viscoelastic effects quantitatively and has been abandoned in favor of the reptation model. 

The Curtiss-Bird theory has been extended to include polydispersity effects extensive data comparisons for the steady-state shear compliance and various nonlinear rheological properties further support the inclusion of the link-tension coefficient in the theory. 

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