Ternary cloud point

Phase separation in ternary systems may be studied using the cloud point isotherm method. Solvent, here defined as component 1, is added to a turbid mixture containing a mixture of components 2 and 3 until the agitated mixture becomes clear. A series of such experiments at various component 2-component 3 weight ratios establishes the cloud point... 

Aharoni, S. M., "Bimodal Closed Cloud Point Curves of Ternary Systems," Macromolecules, 11, 277 (1978). 

Kawata, K. Imagawa, I. Nakata, M., "Cloud-Point Curves of Ternary System Nitroethane + Cyclohexane + Polystyrene Determined by a Novel Method," Polym. J., 23, 233... 

The phase-separation behavior of quasibinary systems is different from that of binary systems. This phenomenon can be most simply described in terms of the cloud-point curves of ternary systems consisting of a solvent and two monodisperse solutes. The cloud-point curve corresponds to the special case of phase separation where the volume of one of the phases tends toward zero. 

Cloud points were determined for a given concentration of polystyrene in the C02-free toluene solution, Cqb, and the given equilibrium C02-pressure of the ternary system. Volume expansion coefficients of the ternary system are given in Chapter 6. 

Cloud points of the ternary system are given in Chapter 4. 

In the late 1970s when they looked over the existing literature, Hashizume et al. noticed that even for the simplest of quasi-binary solutions, i.e., ternary solutions containing two homologous polymers in a single solvent, systematic phase equilibrium data were virtually lacking. Since such data seemed essential for testing any proposed expression for g for quasi-binary solutions, they [22] undertook extensive measurements of cloud-point curves, binodals, and critical points on mixtures of two narrow-distribution polystyrenes f4 and flO dissolved... 

Finally, in Figure 9-19, the composition dependence of Tc and critical point was determined over the entire range of 4. We note that, in a ternary solution in which the chain length ratio of the polymer components, P2/P1, is much larger than unity, the critical point for very close to unity happens to hide below the cloud-point curve as in Figure 9-13 and thus becomes unobservable. 

Cosolvent effect of alkyl acrylates on the phase behaviour of poly(alkyl acrylate)supercriti-cal CO2 mixtures has been reported. Cloud-point data to 220 and 2000 bar are presented for ternary mixtures of poly(butyl acrylate)-C02-butyl acrylate (BA) and poly(ethylhexyl acrylate)-C02-ethylhexyl acrylate) (EHA). The addition of either BA or EHA to the respective polymer-solvent mixtures decreases the cloud-point pressures by as much as 1000 bar and changes the pressure-temperature slope of the cloud-point curves from negative to positive, which significantly increases the single-phase region. 

The phase behavior of the binary system ethylene-PEP and the ternary system ethylene-PEP-C02 have been determined in an optical high-pressure cell designed for pressures up to 400 MPa and temperatures up to 450 K. Fig. 8.1 gives a schematic view of the method used for cloud-point measurements. 

MOH Mohsen-Nia, M., Rasa, H., and Modarress, H., Cloud-point measurements for water + poly(ethylene glycol) + salt ternary mixtures by refractometiy method, J. Chem. 

LLE data For LLE, the concentrations of both phases or only of one phase (cloud-point method) are given. In the latter case, binary parameters can be fitted if cloud points on both sides are available. After adjusting the parameters, one should be aware that they do not necessarily describe multicomponent LLEs correctly. If possible, ternary LLE should be integrated into the database to make the parameters more significant. 

There is a large body of literature on phase diagrams for binary and ternary polymer solutions (Rory 1953 Tompa 1956 Cantow 1967 Utracki 1989) and extensive compilations of data (phase diagrams, cloud points, critical temperatures) for numerous systems (e.g., Wohlfarth 2004, 2008 Koningsveld et al. 2001). A few examples of such systems are listed in Table 2.21. 

Figure 3.12. Schematic of the quasibinary section of a ternary (multicomponent) system, Tp, is tile temperature of the precipitation threshold CPC is the cloud-point curve (tlw phase boundary). / stands for the phase coexistence curves at the total polymer concentration V cj and 4. SL is the shadow line. The concentrations of the coexisting...

Relevant to the study of ternary blends of PCL/phenoxy/PVME are the data on PCL/phenoxy and PCL/PVME binary blends discussed earlier (Sects. 16 and 18.2). Also relevant are studies of phenoxy/PVME blends. Both Robeson et al. [167] and Uriarte et al. [168] demonstrated miscibility over the whole composition range as evidenced by single, composition-dependent TgS the latter group also demonstrated that the binary blends are characterised by LCST behaviour with a rather flat cloud-point curve located at about 430-440 °C over most of the composition range. The same workers determined heats of demixing from the magnitudes of relevant endothermic transitions obtained by differential scanning calorimetry. 

Qipeng demonstrated that PCL/PVME blends were also characterised by single, composition-dependent TgS (Sect. 18.2). Similarly, all ternary blends of the three polymers exhibited single glass transition temperatures which agreed with values calculated from l/T=I(w/Tgj), an extension of Eq. (23) to multiple components. The author concluded that the polymers were miscible in all proportions but made no reference to the occurrence of PCL crystallisation in the samples. Cloud points were also determined in PCL/PVME and phenoxy/PVME blends PCL/phenoxy blends remained clear to 200 °C. All ternary systems exhibited cloud points and the minimum of the connecting surface was 108 °C at a PCL/phenoxy/PVME composition of 25/25/50. 

Figure 3.18. Phase diagram of the ternary system H2O (N)-NMP (S)-PES (P). [Experimental cloud point curve ( ) and lie lines (o).J...

Like the spinodals and binodals of ternary and quaternary polymer blends were calculated with the method(Horst 1995 Horst Wolf, 1992) (the knowledge of the first and second derivatives of AG with respect to the composition variables is not required), the spinodals and the binodals of the PEO/P(EO-b-DMS) system were calculated with the SL theory under different pressures. Figure 15 shows the calculated results of the spinodals and the binodals compared with the experimental data as showed in Figure 14. The dashed and the solid lines represent the spinodals and the binodals calculated with the SL theory under indicated pressures, respectively the open circles represent the experimental data, respectively, which were obtained from Figure 14. In Figure 4 the qualitative agreement between the spinodals and the binodals calculated and the experimental cloud points is acceptable at different pressure. From Figure 15, it can be seen that the critical temperatures (T ) calculated by means of FL theory under different pressure increase with pressure. 

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