ISSN:
1573-4803
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Maschinenbau
Notizen:
Abstract The crystal structure and chain conformation of poly[bis(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 14 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.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00363441
Permalink