Plateau Modulus of Miscible Polymer Blends

We now derive theoretical expressions for G y, for miscible polymer blends using the theory presented in this chapter. For this, let us assume that G° y, can be determined 

When the 3.4-power blending law for the stress relaxation modulus G, (f) is assumed 

The prediction of G, obtained with Eq. (7.58), for comparison, are also given in Eigure 7.36 for PMMA/PVDE blends, showing that Eq. (7.58) predicts 

Some investigators (Composto 1987 Tsenoglou 1988) derived the expression 

We have presented the rheological behavior of several miscible blend systems. In doing so, we discussed the phase behavior of polymer blends in general as determined primarily from DSC and/or cloud point measurement, although other experimental techniques employed are also mentioned or referred to. Since there are many miscible polymer blend systems, we had to select only representative miscible polymer blend systems for the reason of limited space available. Although we have presented the rheological 

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In this chapter, we first present different types of phase behavior in polymer blends, followed by the experimentally observed rheological behavior of some miscible polymer blends. We then present molecular theory for the linear viscoelasticity of miscible polymer blends and compare predictions with experimental results. We present the unresolved issue of determining the plateau modulus of miscible polymer blends. The rheological behavior of immiscible polymer blends will be presented in Chapter 11. 

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