Crystal structure of poly[bis(3,4-dimethylphenoxy)phosphazene] |
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Authors: | T Miyata K Yonetake T Masuko |
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Affiliation: | (1) Faculty of Engineering, Yamagata University, 992 Yonezawa, Japan |
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Abstract: | The crystal structure and chain conformation of polybis(3,4-dimethylphenoxy)phosphazene] — PB (dMe) PP — have been studied by X-ray diffraction techniques. The unit cell of this polymer shows an orthorhombic form with the crystallographic parameters a=2.05, b=1.49, c (chain axis)=0.998 nm. Its space group is determined as Pbcn-D
2h
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where the molecular chains are located at the centre and each corner of the unit cell, which contains eight monomeric units; these molecular chains possibly have a — (trans
3
cis)2-conformation. The R factor calculated from the final crystal structure was estimated as 16.9%. As with other types of polyorganophosphazenes, the thermotropic transformation in PB (dMe) PP takes place from the three-dimensionally ordered state to its two-dimensional psuedohexagonal form (a
h = 1.49 nm), accompanied by a latent heat change at 96 °C. |
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