Web Release Date: December 29,
Influence of Shear on the Templated Crystallization of Poly(butylene terephthalate)/Single Wall Carbon Nanotube Nanocomposites
ndez,
and
Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid, Spain, and European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex, France
Received June 19, 2007
Revised Manuscript Received November 2, 2007
Abstract:
The templating effect due to single wall carbon nanotubes (SWCNT) and shear on polymer crystallization has been studied in films of nanocomposites based on poly(butylene terephthalate) (PBT). With the use of a rheometer, a step shear was applied to the molten polymer. After shear cessation, the sample was immediately cooled down to the crystallization temperature. Crystalline development, in real time, was investigated by small-angle X-ray scattering (SAXS) with a synchrotron radiation beam parallel to the film. SWCNT bundles template polymer lamellae to grow perpendicular to the SWCNT surfaces in a shish-kebab fashion even under quiescent conditions. Because of the power of SWCNT as nucleating agents, the shear rate has a minor effect on the crystallization kinetics. However, the fraction of oriented material increases significantly with shear rate. The results indicate that SWCNT act as nuclei stabilizers, providing surfaces which favor polymer crystallization.
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