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
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Heterogeneous nucleation uniformizing cell size distribution in microcellular nanocomposites foams
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
نویسندگان
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