توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Effect of different solvents and concentration of polymer in the casting solution on the formation of PVDF membranes
اطلاعات انتشار: پانزدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۶
Understanding the mechanism of asymmetric membrane formation is very important in order to produce membranes of desirable morphology.Porous asymmetric poly (vinylidene fluoride) (PVDF) membranes were cast with commercial–grade Kynar K760 polymer pellets and three different solvent systems: N, N–dimethylacetamide (DMAc), N, N–dimethylformamide (DMF) and 1–methyl–2–pyrrolidone (NMP), and with a focus on the PVDF\DMAc system, the effects of concentration of polymer on membrane formation were investigated. Flat–sheet membranes were prepared from a casting solution of polymer in various solvents by immersing the prepared films in nonsolvent–containing of water. The membranes were characterized using scanning electron microscopy (SEM). The differences of solubility parameters between the non solvent, solvent and PVDF affected the phase separation and the resultant morphology. An attempt was made to correlate the effect of the solvent on membrane morphology employing solubility parameters between solvent, non solvent and polymer<\div>

۲Effect of different additives in the casting solution on the formation and morphology of poly (vinylidenefluoride) (PVDF) membranes
اطلاعات انتشار: پانزدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۶
Porous asymmetric hydrophobic membranes were prepared from poly (vinylidenefluoride) (PVDF) polymeric materials by the phase inversion process induced by a nonsolvent. The effect of pore–forming hydrophilic additives on the membrane morphology was investigated. With a focus on the PVDF\DMAc system, the effects of various additives such as Methanol, Glycerol, Lithium chloride (LiCl), Polyethylene glycol (PEG400) and Acetic acid on the resulting membrane morphology were investigated. The thermodynamic precipitation rate of the polymer solution with the different additives was studied using cloud point measurement. The membrane morphology was examined with scanning electron microscopy (SEM). The cross–sectional structure of the membranes showed for different non solvent addtive longer finger–like structure was formed due to rapid liquid–liquid demixing which can be attributed to the strong diffusion power between coagulation bath medium (water) and solvent–nonsolvent additives<\div>
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