ISSN:
1435-1536
Keywords:
Poly(bis(p-flourophenoxy)phosphazene)
;
X-ray diffraction
;
mesophase
;
crystal unit cell
;
thermal transition
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The thermal transition behavior of poly(bis(p-fluorophenoxy)phosphazene) was studied as a representative aryloxy-substituted poly(organophosphazene) using X-ray diffraction, differential thermal analysis and density measurements. The crystal structure ofα-form contained in as-cast film had marked paracrystalline disorder. The crystal phase transformed into the mesophase atT(1) (110 ∼ 140 °C). The structure of theγ-form observed in the mesophase was a representative hexagonal-packing of macromolecular chains which rotate around the chain axes. When the mesophase was cooled to room temperature, a more ordered crystal phase of theβ-form could appear. The most ordered crystal structure of theβ-form has a monoclinic unit cell with the following lattice parameters: a=18.9, b=13.2, c=4.90 Å, andγ=77°. The chain conformation is nearly planar cis-trans, which has been observed commonly in poly(organophosphazenes). The macroscopic deformation of the film sample was also examined, taking into account the microscopic deformation of the lamellar crystal due to the crystal-mesophase transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01469625
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