Unsteady Shear Viscoelastic Properties

Chapters 6 to 9 discuss the steady shear viscous properties, steady shear elastic properties, unsteady shear viscoelastic properties and extensional flow properties, respectively. The effect of filler type, size, size distribution, concentration, agglomerates, smface treatment as well as the effect of polymer type are elucidated. The tenth chapter has been... 

In the preceding two chapters, various effects on steady shear viscous and elastic properties of filled polymer systems were discussed. The present chapter focuses on the unsteady shear viscoelastic properties of these systems. The unsteady shear characteristics are mainly discussed with respect to small-amplitude oscillations, namely, dynamic rheological data. In some cases, the thixotropic sweep responses and the stress relaxation behavior are also included because they bring out the rheological characteristics in some situations in a much better manner. Tbie extensive literature [1-85] on the rheology of filled polymer systems, however, contains quite limited information on the unsteady shear data [1,8,43-45,54,61,62,64,68,71,72,74,91,92]. 

The effect of various parameters on the unsteady shear viscoelastic properties are discussed at varying lengths in the following subsections. 

The smaller the size of the filler, the greater the particle-particle interaction and this reflects greatly on the unsteady shear viscoelastic properties. In the case of complex viscosity vs. frequency curves, it would be natural to expect yield stress with decreasing particle size as... 

Surface modifiers such as those listed in Table 15 are often used in order to achieve better filler dispersion and reduced agglomeration due to improvement in the wettability of the filler and on accoimt of promotion of filler-polymer contact rather than filler-filler contact. The effect of surface treatment on unsteady shear viscoelastic properties has been studied in highly filled systems [43-4554,92] and the available data do provide some basis for understanding the use of surface modifiers. 

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