In-situ SAXS/WAXS investigations of the mechanically-induced phase transitions in semi-crystalline polyamides
| Autor: | Julie Pepin, Valerie Gaucher, Jean-Marc Lefebvre, Cyrille Rochas |
|---|---|
| Přispěvatelé: | Unité Matériaux et Transformations - UMR 8207 (UMET), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut National de la Recherche Agronomique (INRA), Institut de Chimie du CNRS (INC)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Diffraction
Phase transition Materials science Polymers and Plastics Scattering Small-angle X-ray scattering Transition temperature Organic Chemistry 02 engineering and technology [CHIM.MATE]Chemical Sciences/Material chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Crystal [CHIM.POLY]Chemical Sciences/Polymers Chemical physics Materials Chemistry Deformation (engineering) 0210 nano-technology Crystal twinning |
| Zdroj: | Polymer Polymer, Elsevier, 2019, Polymer, pp.87-98. ⟨10.1016/j.polymer.2019.04.073⟩ Polymer, 2019, Polymer, pp.87-98. ⟨10.1016/j.polymer.2019.04.073⟩ |
| ISSN: | 0032-3861 |
| Popis: | The structural evolution under uniaxial tension of both Polyamide-11 (PA11) and Polyamide-6 (PA6) crystallized under various crystal forms has been investigated as a function of draw temperature with respect to the Brill transition. The use of in-situ synchrotron two-dimensional wide-angle X-ray diffraction and small-angle X-ray scattering allows to discriminate thermal from mechanical effects, leading to a revisited scheme of the strain-induced phase transitions in polyamides. It is demonstrated that only the H-bonded sheet-like structures transform mechanically into a pseudo-hexagonal form with a random distribution of H bonds around the chain axis. This order-disorder transition occurs during the fibrillar transformation and seems systematically preceded by a twinning mechanism at low deformation. By contrast, the mesophases and the High Temperature forms are mechanically stable, the latter transforming thermally into the H-bonded sheet-like structures as soon as samples are cooled down below the Brill transition temperature. |
| Databáze: | OpenAIRE |
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