کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5181835 1380973 2014 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Silica nanotubes and hollow silica nanofibers: Gas phase mineralization, polymerization catalysis and in-situ polyethylene nanocomposites
ترجمه فارسی عنوان
نانولوله های سیلیکا و نانوسایل سیلیکا توخالی: کانی سازی فاز گاز، کاتالیزور پلیمریزاسیون و نانوکامپوزیت های پلی اتیلن در محل
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
چکیده انگلیسی

Gas phase mineralization and mesoscopic replication of polyvinyl alcohol (PVA) nanofibers represents an attractive route to the preparation of silica nanotubes and hollow fibers with independent control of pore diameter and wall size. In the sol/gel gas phase process, PVA nanofibers, produced by electrospinning of aqueous PVA, were encapsulated in a thin silica shell by repeated sequenced feed of SiCl4 and H2O vapors, followed by thermal degradation of the PVA core at 550 °C. The hollow fiber wall thickness was governed by the number of SiCl4/H2O cycles with an average increase of the wall size of 0.7 nm per cycle. In contrast to conventional sol/gel electrospinning and wet sol/gel dip coating, shearing of such hollow silicate nanofibers afforded single silica nanotubes with an average length of a few microns. Aqueous silica sols added together with PVA gave control of the inner pore architectures. Methylalumoxane (MAO) activated silica nanotubes were used as supports for half sandwich chromium (III) (Cr) and post metallocene (Fe) catalysts for ethylene polymerization and in-situ nanocomposite formation with uniform dispersion of silica nanotubes within the polyethylene matrix. A blend of Cr and Fe was supported on silica nanotubes to produce melt processable polyethylene nanocomposites with bimodal molecular weight distributions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 55, Issue 2, 30 January 2014, Pages 465-470
نویسندگان
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