X‐ray structure analysis of poly[di‐(3,4‐dimethylphenoxy)phosphazene]

Burkhart, Craig; Gillette, Paul C.; Lando, J. B.; Beres, J. J.

doi:10.1002/pol.1983.180211111

Cited by 14 publications

(9 citation statements)

References 12 publications

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“…This alternate single–double PN bond length character is consistent with results from previous reports 12. 28, 29 The PO and OC bond lengths fall in the range of X‐ray‐determined values for two tris‐spirocyclophosphazenes bearing three 2,2′‐dioxy‐binaphthyl and 2,2′‐dioxy‐biphenyl groups 14. 30…”

Section: Resultssupporting

confidence: 90%

Molecular Dynamics (MD) Simulations and Large‐Angle X‐ray Scattering (LAXS) Studies of the Solid‐State Structure and Assembly of Isotactic (R)‐Poly(2,2′‐dioxy‐1,1′‐binaphthyl‐)phosphazene in the Bulk State and in the Cast Film

Carriedo

Alonso

Alvarez

et al. 2004

Chemistry A European J

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The intrachain conformation, molecular structure and interchain assembly of isotactic (R)-poly(2,2'-dioxy-1,1'-binaphthyl)phosphazene (P-DBNP) both in the bulk state (I) and in the cast film (II) were studied by molecular dynamics (MD) simulations of models, as implemented by a bias potential for the analysis of the radial distribution function (RDF) obtained from large-angle X-ray scattering (LAXS) data. The microscopic structure and order extension of the polymer changed from I to II, as qualitatively shown in the shapes of their experimentally measured RDF curves. With the use of a bias potential, the MD simulations provided a much more accurate analysis of the models, as seen in the reproduction of the RDFs. The chiral P-DBNP chain was found to be consistent with helix conformations in both the I and the II samples. The predominant interchain clustering motif was best reproduced with a seven-chain model. In the case of I, the maximum chain length was 18 monomeric -R(2)NP- units, while in the case of the cast film II the chain was more elongated, up to distances of approximately 100 A, equivalent to over 48 monomeric -R(2)NP- units. The seven-chain assembly was accounted for in terms of nonbonded interactions favouring the minimum voids area between the seven tubular structures of the material. The results validate our earlier finding that MD analysis with implementation of a biasing potential for the RDFs can provide quantitative information on the structural and conformational features of amorphous solids. The combined theoretical and experimental approach was found to be a useful tool to detect, locate and evaluate the intra- and intermolecular modifications of materials subsequent to their phase transformation and, as in the present case, changes in their microscopic structures or preparation methods.

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Section: Resultssupporting

confidence: 90%

Molecular Dynamics (MD) Simulations and Large‐Angle X‐ray Scattering (LAXS) Studies of the Solid‐State Structure and Assembly of Isotactic (R)‐Poly(2,2′‐dioxy‐1,1′‐binaphthyl‐)phosphazene in the Bulk State and in the Cast Film

Carriedo

Alonso

Alvarez

et al. 2004

Chemistry A European J

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“…It is well known the transition is reversible with some hysteresis whenever heating/ cooling differential scanning calorimetry (DSC) scans are made. Morphological and structural investigations [12][13][14][15][16][17][18][19][20][21][22] , thermal analysis 9,11) , crystallization kinetics 23,24) , NMR 11) , dilatometry 4,11) , and dynamical mechanical measurements 3) have been reported for PBFP on either side of this thermotropic transition. Above T (l), the backbone chains of the mesophase are pseudo-hexagonally packed.…”

Section: Introductionmentioning

confidence: 99%

High temperature behavior of poly[bis(2,2,2-trifluoroethoxy)phosphazene]

Nakamura¹,

Masuko²,

Kojima³

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: Mesomorphic features of poly[bis(2,2,2-trifluoroethoxy)phosphazene] (PBFP) with high (L10 7 ) and low (L10 4 ) molecular weights have been investigated by X-ray diffraction techniques, differential scanning calorimetry optical and electron microscopy, and small-angle X-ray scattering. Characterization measurements were made from room temperature to L300 8C, which is well above T m , the designated melting temperature of PBFP. The wide angle X-ray scattering (WAXS) may be interpreted in support of some kind of "nano-scale order" persisting above the isotropization temperature, T m , of this polymer. There is other evidence to the contrary, namely the optical isotropicity between crossed-polars (depicts melting) and the absence of discrete small angle X-ray scattering (SAXS) under these same conditions. An attempt is made here to establish if these features above T m are related to molecular weight.

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“…Structural investigations7'15 on these polymers have been concentrated exclusively on the morphology, crystal modification, and the phase transition, and hence little is known about their molecular and crystal structures. 16,17 In order to establish a base line for examining the crystal structures of poly(organophosphazenes), we have reexamined the crystal structure of PDCP.…”

Section: Introductionmentioning

confidence: 99%