Energy spinodal decomposition, polymer blends

In the melt phase, thermodynamics would indicate that chains with different chain lengths should have different energies. As a consequence there is the possibility that chains with a similar energy will tend to segregate themselves in space. Phase separation is well known in polymer blends (Chapter 8) and can be described by the process of spinodal decomposition. In the case of a broad molecular mass distribution polymer system, the individual chains will... 

The solvent in the blends can increase the mobility of the polymer molecules and decrease the interaction force between the macromolecules. From Figure 15.18, it can be seen that the solvent in an immiscible polymer pair can decrease the free energy level of the system and increase the miscibility of the two polymers. Therefore, the solvent concentration can influence the resultant pattern in the spinodal decomposition indeed, the solvent concentration can be changed to investigate the influence of solvent composition on the morphology of phase separation. The morphology evolution of ternary systems with different solvent composition is shown in Figure 15.22 in this case the initial condition is the same. 

Figure 2.16 Analysis of phase behaviour of a binary blend of polymer and solvent or two polymers exhibiting an upper critical solution temperature, Top variation of Gibbs free energy with composition, 0(0 = 0i or 02) at four temperatures. The tie line CC defines the compositions on the binodal curve. The locus of points defined by the points of inflection (9 G/90 )t,p = 0 define the spinodal curve. At point A (inside the spinodal curve), the mixture will spontaneously phase separate (into domains with compositions 0 and 0") via spinodal decomposition. However, at point B (outside the spinodal curve) there is an energy barrier to phase separation, which then occurs by nucleation and growth...

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