Abstract
The existence of mesomorphism in polydiethylphosphazene was recently established by MAS NMR and X-ray diffraction characterization. In the present work the mechanism of motion of the ethyl side groups in the high-temperature polymorph tabove 45 C) is identified and compared to the arrangement of side groups in the low-temperature polymorph. For this purpose a few NMR active nuclei (13C,14N, and2H) were exploited to define the side-chain motions occurring at transition. Experiments performed at varying temperatures close to the onset of solid transition suggest the presence of jumps between two conformations in the pretransition state. Rotor-synchronized triple-resonance NMR of the high-temperature phase determined the average distances between the carbons and the nitrogens in the polymorphs. The theoretical prediction of the dipolar interaction between the nuclei supports the hypothesis that ethyl groups can undergo a complete rotation about the P CH2 bond by jumping across a conformational barrier. The mechanism of motion of the ethyl groups must be cooperative and the collapse of the rigid shell around the main chain is described at the transition.
Similar content being viewed by others
References
R. H. Nielson, R. Hani, P. Wisian-Neilson, J. J. Meister, A. K. Roy, and G. L. Hagnauer,Macromolecules 20, 910 (1987).
P. Wisian-Neilson and R. H. Nielson,Inorg. Chem. 25, 69 (1989).
V. S. Papkov, M. N. Il'ina, V. P. Zhukov, D. Ja. Tsvankin, and D. R. Tur.Macromolecules 25, 2033 (1992).
D. R. Tur, N. P. Provotorova, S. V. Vinogradova, V. I. Bakhumutov, M. V. Galakhov, V. P. Zhukov, I. I. Dubovik, D. Ja. Tsvankin, and V. S. Papkov,Makromol. Chem. 192, 1905 (1991).
H. R. Allcock, C. G. Cameron, T. W. Skloss, S. Taylor-Meyers, and J. F. Haw,Macromolecules 29, 233 (1996).
M. Kojima and J. H. Magill,Polymer 30, 579 (1989).
D. C. Sun and J. H. Magill,Polymer 28, 1243 (1987).
M. A. Gomez, C. Marco, J. C. Fatou, T. N. Browmer, R. C. Haddon, and S. V. Chichester-Hicks.Macromolecules 24, 2301 (1991).
C. R. Desper and N. S. Schneider,Macromolecules 9, 924 (1976).
J. H. Magill and C. Rickel,Makromol. Chem. Rapid Commun. 7, 287 (1986).
H. Tanaka, M. A. Gomez, A. F. Tonelli, S. V. Chichester-Hicks, and R. C. Haddon,Macromolecules 21, 2301 (1988).
S. V. Meille, A. R. Poletti, M. C. Gallazzi, M. Gleria, and S. Bruckner,Polymer 25, 2364 (1992).
S. V. Meille, M. C. Gallazzi, and A. Farina,Makromol. Chem. Rapid Commum. 15, 573 (1994).
M. Kojima and J. H. Magill,Makromol. Chem. 193, 2731 (1992).
S. V. Meille, A. Farina, M. C. Gallazzi, P. Sozzani, P. Sozzani, R. Simonutti, and A. Comotti,Macromolecules 28, 1893 (1995).
S. A. Taylor, J. I. White, N. C. Flbaum, R. C. Crosby, G. C. Campbell, J. F. Haw, and G. R. hatfield.Macromolecules 25, 3369 (1992).
H. Tanaka, M. A. Gomez, A. F. Tonelli, S. V. Chichester-Hicks, and R. C. Haddon,Macromolecules 22, 1031 (1989).
P. Wisian-Neilson and R. H. Neilson.Inorg. Synth. 25, 69 (1989).
C. P. Grey and W. S. Veeman.Chem. Phys. Lett. 192, 379 (1992).
R. Simonutti, M. C. Gallazzi, E. C. Rurihau, W. S. Veeman, and P. Sozzani,Macromolecules 29, 4958 (1996).
E. A. Bovey,Nuclear Magnetic Resonance Spectroscopy. Academic Press, London, 1987).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Simonutti, R., Comotti, A. & Sozzani, P. Mesomorphic behavior of polydiethylphosphazenes as described by13C,14N, and2H NMR. J Inorg Organomet Polym 6, 313–324 (1996). https://doi.org/10.1007/BF01062512
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01062512