The effects of precipitation temperature on the structures of the EVAL membranes formed in a wet phase inversion process were studied. As the temperature was changed, the phase behavior (liquid–liquid demixing and crystallization boundaries) of the membrane formation system changed accordingly. Therefore, a wide variety of morphologies of the EVAL membranes could be synthesized at different temperatures. At low temperatures (e.g., 25°C), the membrane solution precipitated into a particulate morphology that was governed by the polymer crystallization mechanism, whereas at elevated temperatures (e.g., 65°C) liquid–liquid demixing process dominated the precipitation process and the membrane became cellular in its morphology. In the intermediate cases, the membrane exhibited a structure containing features from both types of phase separations. For the current system, it was found that there existed a good correlation between the phase behavior and the morphology of the membranes.
Посилання на статтю:
Prediction of EVAL membrane morphologies using the phase diagram of water–DMSO–EVAL at different temperatures / Tai-Horng Young, Liao-Ping Cheng, Wei-Ming You, Li-Yen Chen // Polymer. – 1999. – N 40. – P. 2189–2195.