کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5188805 1381169 2006 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Supercritical CO2 dispersion of nano-clays and clay/polymer nanocomposites
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Supercritical CO2 dispersion of nano-clays and clay/polymer nanocomposites
چکیده انگلیسی
Dispersed polymer/clay nanocomposites are of great interest because they can significantly improve the properties of existing polymeric materials. However, achieving a high level of clay dispersion has been a key challenge in the production of polymer/clay nanocomposites. In this paper, we explore a novel supercritical carbon dioxide (scCO2) processing method that utilizes scCO2 to disperse nano-clays. The structure and properties of the clays and the resultant nanocomposites are characterized using a combination of wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and rheology. Significant dispersion was achieved with dry Cloisite 93A clay, whereas relatively poor dispersion was achieved with dry Cloisite Na+ (natural clay). The extent of clay dispersion appears to be dependent on the 'CO2-philicity', which in turn appears to depend on the surface modifications and inter-gallery spacing. The presence of an acidic hydrogen on the surfactant in Cloisite 93A appears to play a strong role in its 'CO2-philicity'. The ability to delaminate dry clays is significant because it will likely increase the ability to produce dispersed clay/polymer nanocomposites via melt processing. In addition to delaminating dry clays, we demonstrate that CO2-phobic Cloisite Na+ (natural clay) can be partially dispersed with scCO2, using a CO2-philic polymer, polydimethylsiloxane (PDMS). The dispersed clay/PDMS nanocomposite shows an order of magnitude increase in the dynamic storage modulus at low frequencies, accompanied by the emergence of a 'solid-like' plateau, characteristic of dispersed nanocomposites with enhanced clay/polymer interactions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 47, Issue 21, 4 October 2006, Pages 7485-7496
نویسندگان
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