Solvent-Free Preparation of High-Toughness Epoxy−SWNT Composite Materials
| Autor: | Hartmut Stadler, Mohammed Naffakh, Alejandro Ansón-Casaos, Marián A. Gómez, Behnam Ashrafi, M. Teresa Martínez, David Backman, Jose M. González-Domínguez, Ana M. Díez-Pascual, Andrew Johnston |
|---|---|
| Přispěvatelé: | National Research Council of Canada, Ministerio de Ciencia e Innovación (España) |
| Rok vydání: | 2011 |
| Předmět: |
Toughness
Materials science Carbon nanotube Impact strength Miscibility Tensile strength law.invention Atomic force microscopy Electric conductivity Single-walled carbon nanotubes (SWCN) law Ultimate tensile strength Detrimental effects Epoxy nanocomposites General Materials Science Composite material Electrical percolation threshold Nanocomposite Izod impact strength test Composite materials Epoxy Block copolymers Organic solvents visual_art Solvents visual_art.visual_art_medium Dynamic mechanical behavior Dispersion (chemistry) |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1944-8252 1944-8244 |
| DOI: | 10.1021/am101260a |
| Popis: | Multicomponent nanocomposite materials based on a high-performance epoxy system and single-walled carbon nanotubes (SWNTs) have been prepared. The noncovalent wrapping of nitric acid-treated SWNTs with a PEO-based amphiphilic block copolymer leads to a highly disaggregated filler with a boosted miscibility in the epoxy matrix, allowing its dispersion without organic solvents. Although direct dispersion of acid-treated SWNTs results in modestly improved epoxy matrix mechanical properties, the incorporation of wrapped SWNTs produces a huge increase in toughness (276% improvement at 0.5 wt % loading) and impact strength (193% at 0.5 wt % loading) with no detrimental effect on the elastic properties. A synergistic effect between SWNTs and the block copolymer is revealed on the basis of tensile and impact strength results. Atomic force microscopy has been applied, obtaining stiffness mappings that identify nanostructure features responsible of the dynamic mechanical behavior. The electrical percolation threshold is greatly reduced, from 0.31 to 0.03 wt % SWNTs when block copolymer-wrapped SWNTs are used, and all the measured conductivity values increased up to a maximum of 7 orders of magnitude with respect to the baseline matrix (1 wt % wrapped-SWNTs loading). This approach provides an efficient way to disperse barely dispersible SWNTs without solvents into an epoxy matrix, and to generate substantial improvements with small amounts of SWNTs. The authors thank financial support from the NRC (Canada) − CSIC (Spain) collaboration project and also thank Huntsman company. Mr. González-Domínguez gratefully acknowledges the Spanish Ministry of Innovation (MICINN) for his FPU predoctoral grant. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|