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particular system [2]. Figure 1 shows the ternary phase diagram for the NIPS process in membrane formation. The line with points A, B, C, and D denotes the path that the membrane takes during this process. At point A, phase inversion has not begun, and the casting solution only consists of solvent, polymer, and additives.
The ternary phase diagram obtained for of polyethersolfune (PES)/n-methyl-2-pyrrolidone (NMP)/water ternary system is illustrated in Fig. 6, where the thermodynamic boundaries of binodal, spinodal, gelation and vitrification are shown.
Many of the processes used to make separation membranes require dissolving the polymer in a solvent. Because Solef® PVDF, Udel® PSU, Veradel® PESU and Radel® PPSU are soluble in conventional solvents, they can be solvent cast by the Diffusion Induced Phase Separation (DIPS) process.
Thermodynamic stability of casting solution with different solvents based on ternary phase diagrams. Detailed influence of solvent sorts on the membrane structure. Membrane formation mechanism based on thermodynamic and kinetic properties of casting solution.
The solutions of the model comprised the volume fractions of the three species in position and time. Polymer concentration evolutions (an example is shown in Fig. 5 (A)) were superposed on a ternary phase diagram, like that in Fig. 3, to give composition paths in the cast film Fig. 5 (B).
In this work, we focused on development of a reliable method of phase diagram construction i.e. determination of thermodynamic boundaries, where a compressible regular solution theory based model (CRS) has been used to resolve the essence of experimental knowledge on interaction parameters of models such FloryeHuggins.
From a thermodynamic point of view, study on polymer– solvent– nonsolvent system can be well depicted in a ternary phase diagram. The Flory-Huggins theory was found to be a convenient and useful framework for the thermodynamic analysis of component mixing in a membrane preparation system.
In this study, we conducted simulations of phase separation in both Temperature Induced Phase Separation (TIPS) binary (polymer/solvent) and Non-solvent Induced Phase Separation (NIPS) in ternary (polymer/solvent/non-solvent) systems using 2D and 3D models.
Ternary phase diagrams can predict, whether or not a solution of a certain polymer in a certain solvent is suitable for membrane formation. Binary phase diagrams indicates the phase boundaries as a function of
Different compositions of polymer solutions were established along the binodal boundaries of the respective systems, derived from experimental cloud point data on the ternary phase diagram. The resulting polymer membranes were analyzed and compared in terms of their morphology.