S2

] phase

or P2

Figure 1. Schematic representation of the influence of various factors on the miscibility and phase separation. The shaded areas represent the two-phase regions. The arrows show the paths for phase separation, while the reverse directions would be the paths for miscibility. From left-to-right: Temperature-induced phase separation; solvent-induced phase separation; reaction (i.e. polymerization) -induced phase separation (the two-phase regions are entered with increasing degree of polymerization (DP)); and pressure-induced phase separation. ^ = polymer concentration, S2 and S1 solvent and nonsolvent; P1 and P2 = polymer 1 and polymer 2.

or P2

Figure 1. Schematic representation of the influence of various factors on the miscibility and phase separation. The shaded areas represent the two-phase regions. The arrows show the paths for phase separation, while the reverse directions would be the paths for miscibility. From left-to-right: Temperature-induced phase separation; solvent-induced phase separation; reaction (i.e. polymerization) -induced phase separation (the two-phase regions are entered with increasing degree of polymerization (DP)); and pressure-induced phase separation. ^ = polymer concentration, S2 and S1 solvent and nonsolvent; P1 and P2 = polymer 1 and polymer 2.

must be reduced either to recover a product, or the processing fluid. A particularly important aspect of the pressure-induced phase separation that differentiates it from the other techniques is the fact that the pressure changes can be brought about uniformly and very fast throughout the bulk of a solution. This would not be so in other techniques due to, for example, heat and mass transfer limitations that would influence the rate of phase separation in the case of temperature- and solvent-induced phase separations, respectively. It is however important to note that temperature, solvent, reaction, or field-induced phase separation may also be carried out at elevated pressures if desired, and therefore all modes of phase separation methods are of interest when working with near-critical or supercritical fluid systems.

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