کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5188814 | 1381169 | 2006 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Heterogeneous nucleation uniformizing cell size distribution in microcellular nanocomposites foams
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
Microcellular polycarbonate/nano-silica nanocomposites (PCSN) were prepared by temperature rising process using supercritical CO2 as the blowing agent. Neat PC foam showed a quite broad distribution of cell sizes. Under the same foaming conditions, the addition of nano-silica resulted in PCSN foams having uniform cell size distribution, reduced cell size of 0.3-0.5 μm and increased cell density of 1011-1013 cells/cm3. The underlying nucleation mechanism was semi-quantitatively analyzed by the classical nucleation theory. The results indicate that the energy-barrier for heterogeneous nucleation was three orders of magnitude lower than that of homogeneous one. The heterogeneous nucleation of nano-silica aggregates dramatically increased the nucleation rate, decreased the nucleation time interval, and hence facilitated the almost instantaneous growth of cell size. Combined with the well-dispersed nucleation sites, resulted from the uniform dispersion of nano-silica aggregates, the narrow-distributed cell size was obtained in PCSN foams.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 21, 4 October 2006, Pages 7580-7589
Journal: Polymer - Volume 47, Issue 21, 4 October 2006, Pages 7580-7589
نویسندگان
Wentao Zhai, Jian Yu, Lichuan Wu, Weiming Ma, Jiasong He,