کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
638204 1456161 2008 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Comparison of diamino cross-linking in different polyimide solutions and membranes by precipitation observation and gas transport
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
Comparison of diamino cross-linking in different polyimide solutions and membranes by precipitation observation and gas transport
چکیده انگلیسی

Matrimid and 6FDA-durene polyimides (PI) are chosen to investigate diamino cross-linking processes in solution and dense membrane forms. The cross-linking process (precipitation) of polyimide solutions is visually monitored by a digital camera to provide visual evidence for the chemical reaction. By comparing the reaction of different diamines with the polyimide solutions, we inferred that the cross-linking rate is an indication of the nucleophilicities of the diamines. The cross-linked network in Matrimid/dichloromethane (CH2Cl2) solutions appeared much faster than that in 6FDA-durene/CH2Cl2 solutions. Interestingly, the cross-linking of 6FDA-durene membranes by the same diamine resulted in a greater decline in gas permeability as compared to that of Matrimid membranes due to the different electrophilicity of polyimides and the different diffusion rate of diamines into membranes. FTIR, XPS, XRD, TGA and gas transportation test are applied for analyzing the cross-linking mechanism and properties of polyimide membranes. Gas pair selectivities of H2/CO2, H2/N2, O2/N2 and CO2/CH4 were enhanced upon the cross-linking of 6FDA-durene by diamines. In contrast, for Matrimid, an improvement in gas pair selectivities of H2/CO2, H2/N2 and O2/N2 was achieved but a less favorable CO2/CH4 selectivity was observed after diamino cross-linking.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 312, Issues 1–2, 1 April 2008, Pages 174–185
نویسندگان
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