Phase structure and transitions in a poly(methyloctadecylsilane) oligomer
Data(s) |
2001
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Resumo |
A poly(methyloctadecylsilane) oligomer was synthesized by a typical Wurtz coupling reaction. Upon cooling, three transitions were observed at temperatures of 39.9, 37.5 and 33.9 degreesC at a rate of 2.5 degreesC/min in differential scanning calorimetry (DSC). The first transition, with enthalpy change of 0.47 kT/mol and supercooling of 0.2 degreesC, was characteristic of the conformational change in the Si-Si backbone into an all-trans conformation, which was detected by temperature-dependent Fourier transform infrared (FT-FR) spectroscopy. The second and the third transitions with large supercooling were identified as the formation of two-dimensional hexagonal crystal packing and three-dimensional two-chain orthorhombic crystal packing, respectively. The crystal structure was determined by the combination of WAXD and transmission electron microscopy (TEM) experiments. (C) 2000 Elsevier Science Ltd. All rights reserved. |
Identificador | |
Idioma(s) |
英语 |
Fonte |
Wu ZM;Xie FC;Hu ZJ;Liu JP;Du BY;He TB.Phase structure and transitions in a poly(methyloctadecylsilane) oligomer,POLYMER,2001,42(3):1047-1053 |
Palavras-Chave | #LIQUID-CRYSTALLINE POLYSILANE #TO-COIL TRANSITION #POLYETHERS |
Tipo |
期刊论文 |