On the molecular mechanism of the crystal transformation (tetragonal-hexagonal) in polybutene-1 |
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Authors: | R M Gohil M J Miles J Petermann |
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Institution: | 1. Universit?t des Saarlandes , Werkstoffphysik, 6600, Saarbrücken, West Germany;2. Universit?t des Saarlandes , Werkstoffphysik, 6600, Saarbrücken, West Germany;3. University of Bristol , Bristol, United Kingdom |
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Abstract: | The phase transformation from the tetragonal to the hexagonal crystal modification in highly oriented lamellae of poly-butene-1 has been followed by transmission electron microscopy (TEM). It is found that the reaction-controlling step is the nucleation process. No lattice orientation relationship (besides the 001]-direction, which is parallel in both crystal modifications) exists between non-transformed and transformed crystals. The nucleation is strongly enhanced by thermal or external stresses. Crystal growth, nucleated by external stresses, was observed at temperatures as low as — 150°C. The molecular mechanisms of the transformation are discussed. |
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Keywords: | Poly(ethylene terephthalate) Supercritical fluid dyeing Fiber structure High-speed spinning |
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