Morphological features and melting behavior of nanocomposites based on isotactic polypropylene and multiwalled carbon nanotubes |
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| Authors: | Carlos A. Avila‐Orta Francisco J. Medellín‐Rodríguez Mario V. Dávila‐Rodríguez Yrayda A. Aguirre‐Figueroa Kyunghwan Yoon Benjamin S. Hsiao |
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| Affiliation: | 1. Departamento de Materiales Avanzados. Centro de Investigación en Química Aplicada, Blvd. Enrique Reyna H. No. 140, Saltillo, Coah 25253, México;2. CIEP/FCQ. Universidad Autónoma de San Luis Potosí, Dr. Manuel Nava No. 6, San Luis Potosí SLP 78210, México;3. Instituto Tecnológico de Saltillo, Blvd. Venustiano Carranza No. 2400, Saltillo, Coah 25280, México;4. Department of Chemistry. Stony Brook University, Stony Brook, NY 11794‐3400, USA |
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| Abstract: | Nanocomposites based on low molar mass isotactic polypropylene (iPP) and a low concentrations (1–2 wt %) of multiwalled carbon nanotubes (MWCNTs) were studied using thermal analysis, optical and electronic microscopy, and X‐ray diffraction/scattering techniques. It was first determined that MWCNT decrease induction time and act as nucleating agents of the iPP crystals during nonisothermal crystallization. One of the consequences of the nucleation effect was that the original spherulitic morphology of iPP was transformed into a fibrillar‐like. The corresponding long period of the original well‐defined lamellar structure slightly increased suggesting the formation of thicker crystals in samples containing MWCNT. The nature of the α‐iPP crystalline structure was not affected by MWCNT. After nonisothermal crystallization, two melting endotherms were present during thermal scanning of the iPP/MWCNT nanocomposites their proportion changing with the heating rate. After resolving the total DSC signal in its components using MDSC, the overall evolution of such behavior could be explained in terms of the melting/recrystallization mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 |
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| Keywords: | morphology crystallization melting |
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