کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5189062 | 1381176 | 2008 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Morphological changes in poly(É-caprolactone) in dense carbon dioxide
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Morphological changes that take place in poly(É-caprolactone) upon exposure to carbon dioxide at high pressures have been explored as a function of pressure and temperature. SEM and DSC results point to a competition between CO2-modulated crystallization and pressure-induced phase separation which leads to unique morphologies. At 293Â K, exposure to CO2 at pressures up to 45Â MPa leads to recrystallization resulting in higher level of crystallinity and higher melting temperatures. Highest crystallinity levels along with distinct crystal morphology were observed after exposure to CO2 at 308Â K and 21Â MPa. At a higher pressure at this temperature (308Â K/34Â MPa) polymer undergoes melting, and foaming is achieved during depressurization prior to solidification. At 323Â K, the polymer is found to display unique crystal morphology with concave crystal geometry as well as porous domains. The results are discussed in terms of the crystallization and phase separation paths that are followed during exposure to CO2 and the depressurization stages.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 49, Issue 7, 1 April 2008, Pages 1853-1859
Journal: Polymer - Volume 49, Issue 7, 1 April 2008, Pages 1853-1859
نویسندگان
Erdogan Kiran, Kun Liu, Katrina Ramsdell,