Solutions, Plasticized Polymers, and Gels

The present chapter deals only with concentrated solutions, which might be defined for convenience, in accordance with Section D of Chapter 9, as those with the product c[tj] of at least 10. Such a solution usually has a relative viscosity of the order of at least 100, though it depends on the polymer, the solvent, and the temperature. The viscoelastic properties of more dilute solutions have already been reviewed in Chapter 9. The upper limit of the concentration range in the present chapter is the undiluted polymer. There is considerable interest in the properties of systems containing only small amounts of diluents or plasticizers. Gels, or diluted cross-linked systems, are also considered in this chapter. 

The effects of a diluent or plasticizer on viscoelastic properties in the transition zone can be analyzed in terms of its influence on the temperature dependence function, arit), and, separately, on the absolute values of friction coefficients and the shapes of viscoelastic spectra. 

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