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NMR studies of molecular motion of ultradispersed polytetrafluoroethylene |
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| Authors: | V M Buznik A I Livshits M Ol’shevskii A R Semenov N A Sergeev |
| Institution: | (1) G. K. Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences, Novosibirsk;(2) Institute of Chemistry and Chemical Technology, Siberian Division, Russian Academy of Sciences, Krasnoyarsk;(3) Institute of Physics of Szczecin University, Poland;(4) A. V. Nikolayev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, Novosibirsk |
| Abstract: | Molecular motion in ultradispersed polytetrafluroethylene obtained by special gas-phase technology has been studied experimentally and theoretically based on a temperature dependence of the second moment of 19F NMR spectra and the time of spin-lattice relaxation. The results of observations are interpreted as the consequence of reorientation motion of CF2 groups around the axis of macromolecules at low temperature and of translational motion of macromolecules in the high temperature region. Qualitative differences from the molecular motion in industrial polytetrafluoroethylene (teflon-4) were detected and parameters of dynamic processes determined. |
| Keywords: | ultradispersed polytetrafluroethylene molecular motion NMR the second moment spin-lattice relaxation |
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