Solvent phase diagrams

Figure 2.33 Polymer-solvent phase diagram showing binodal, spinodal, and miscibility gap. Reprinted, by permission, from J. M. G. Cowie, Polymers Chemistry Physics of Modem Materials, 2nd ed., P. 167. Copyright 1991 by Chapman Hall.

The model of Marchetti et al. is based on the compressible lattice theory which Sanchez and Lacombe developed to apply to polymer-solvent systems which have variable levels of free volume [138-141], This theory is a ternary version of classic Flory-Huggins theory, with the third component in the polymer-solvent system being vacant lattice sites or holes . The key parameters in this theory which affect the polymer-solvent phase diagram are ... 

The main features of the polymer - solvent phase diagram can be obtained at the simple Flory - Huggins level [11,73] In effect, this theory leads to the following predictions for the dependence of the position of the critical point on the molecular mass (M —> oo) ... 

Fig. 1.9 Calculated polymer-solvent phase diagram. The bimodal (continuous line) is the coexistence curve the points below it correspond to thermodynamically unstable states, which undergo phase separation. However, the pints between the bimodal and the spinodal (dashed line) are ki-netically stable, since there is a free-energy barrier to phase separation. C indicates the critical point the collapse temperature. The deviation of the low-concentration branch of the spinodal from the vertical axis below T is an artifact of the mean-field approximation. (From ref. [62])...

Figure 37c shows the alkane—solvent phase diagram calculated by equating A = BE (top curve equilibrium liquidus) and A = BF (bottom curve metastable liquidus). Imagining that crystal growth rate G is plotted on the x-axis, and bearing in mind that on either of the liquidus lines G is zero, the c and T dependencies of G in Figure 37a and b can be... 

Figure 1. Schematic plots of polymer/polymer/solvent phase diagrams for (a) two miscible polymers plus a solvent Inducing phase separation, (b) two immiscible polymers. The lines AB and CD show evaporation pathways.

Ethylene-o-dichlorobenzene system, 39 Ethylene glycol, 181,182, 327 Ethylene-methanol system, 183 Ethylene-naphthalene system, 69 Ethylene-polyethylene system, 319 Ethylene-n-propanol system, 39 Ethylene-water-organic solvent phase diagrams, 71 Explosives, 347 Extractibility, 367... 

Dubault, A., Casagrande, C., and Veyesie, M., Flexible polymers in nematic solvents phase diagrams in dilute regime. Mol. Cryst. Liq. Cryst., 72,189-194 (1982). 

D. Brouillette, D. E. Irish, N. J. Taylor, G. Perron, M. Odziemkowski, J. E. Desnoyers, Phys. Chem. Chem. Phys. 2002, 4, 6063-6071. Stable solvates in solution of lithium bis(trifluoromethylsulfone)iniide in gjymes and other aprotic solvents Phase diagrams, crystaUogiaphy and Ramtm spectroscopy. 

Keywords Modeling Mixed solvents Phase diagrams Polymer solutions Ternary mixtures Thermodynamics... 

More importantly, the crystalline-solvent phase diagrams, thus solved in the context of the Flory-Huggins theory alone, cannot account for the existence of the solidus line, because the crystal phase always coincides with the pure crystalline polymer axis due to the inherent assumption, adopted from Prigogine theory, of the complete rejection of solvent molecules from the crystaHine phase [66,67]. Thus,... 

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