کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1402217 984753 2010 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of the preparation conditions on the formation of asymmetric poly(vinylidene fluoride) hollow fibre membranes with a dense skin
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Effect of the preparation conditions on the formation of asymmetric poly(vinylidene fluoride) hollow fibre membranes with a dense skin
چکیده انگلیسی

Integrally skinned asymmetric poly(vinylidene fluoride) hollow fibre membranes were prepared and characterized. The effects of phase inversion methods (dry-wet or wet) and spinning conditions, such as the type of solvent (NMP, DMAc), the concentration of polymer in dope solution, temperature of the external coagulation bath and the composition of the inner coagulant on the morphology and on the formation of a dense skin layer were investigated. The structure of the membranes was analyzed by scanning electron microscopy and the gas permeation properties with six different gases (He, H2, N2, O2, CH4 and CO2) were measured at 25 °C to confirm the integrity of the selective skin layer. Under the proper conditions highly selective and permeable PVDF hollow fibre membranes were thus obtained by dry-wet spinning of a 30 wt.% PVDF solution in DMAc, using hot water (50 °C) as the external coagulant and a bore fluid of pure water as the internal coagulant. The best membrane had a selective outer skin with an effective thickness of approximately 0.2 μm. The ideal selectivity of the hollow fibres approached or even exceeded the intrinsic ideal selectivity of a dense PVDF film, for instance the selectivity for He over N2 was 86.2 for the hollow fibre, whereas it was 83.5 for a dense PVDF reference film. DSC and FT-IR/ATR analysis indicated a higher fraction of the β-crystal phase in the selective skin and a high overall crystallinity than in the melt-processed film. The latter explains the relatively high selectivity and low permeability of the membranes. Intrinsic polymer properties make the membranes also suitable for vapour transport than for gas separation.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Polymer Journal - Volume 46, Issue 8, August 2010, Pages 1713–1725
نویسندگان
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