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Lysenkov E.A.,Mykolayiv National University Named After Vosukhomlynskiy | Klepko V.V.,Institute of Macromolecular Chemical NAS of Ukraine
Journal of Nano- and Electronic Physics | Year: 2016

The basic theoretical models of electrical conductivity of polymer nanocomposites and their accordance to experimental results are analysed for the systems based on polyethers and carbon nanotubes using the methods of mathematical simulation. It is set that models which are based on the effective medium approximation do not take into account existence of percolation threshold and can't be using for exact definition of experimental data. It is discovered that the Fourier model demonstrats a good accordance with an experiment, however it is applicable only for the systems in which a large increase of conductivity under reaching the percolation threshold is observed, that systems with low own conductivity. It is set that the best accordance to experimental data was shown by the Kirkpatrick model and the generalized McLachlan model, which, except for the percolation threshold, structural descriptions of clusters which are formed from carbon nanotubes take into account. © 2016 Sumy State University.


Lysenkov E.,Vo Sukhomlynskyi Mykolayiv National University | Melnyk I.,Taras Shevchenko National University | Bulavin L.,Taras Shevchenko National University | Klepko V.,Institute of Macromolecular Chemical NAS of Ukraine | Lebovka N.,Biocolloidal Chemistry Institute Named After F D
Springer Proceedings in Physics | Year: 2015

The structure of polyglycols (polyethylene glycol and polypropylene glycol) doped by nanoparticles with anisotropic shape (carbon nanotubes and inorganic nanoplatelets) is discussed. Various experimental methods such as X-ray scattering, optical microscopy, impedance spectroscopy, differential scanning calorimetry and electrical conductivity measurements have been used. Introduction of such nanoparticles results in noticeable changes in the polymer structure even at rather small concentration of fillers (0.3–0.5 wt%). The percolation behaviour is typical for fluid and semicrystalline polyglycols doped with carbon nanotubes. In the vicinity of percolation threshold the entangled network of nanotubes is formed. This network has impact on the kinetics of polymer crystallization, degree of crystallinity, electrical and thermal properties of the composites. Different types of electrical conductivity in these systems were identified. The structure of polyglycols doped with nanoplatelets depends upon the type of the filler. The data evidence the presence of partial intercalation of macromolecules inside the interlayer space of nanoplatelets of organo-modified montmorillonite and the complete exfoliation oforgano-modified laponite platelets inside the polymer matrix. The doping by nanoplatelets also improved the dispersion of nanotubes inside polyglycols. The effects of nanofillers on the behaviour of polymer electrolytes on the base of polyglycols are also discussed. The doping allows decreasing the degree of ionic association, resulting in higher concentration of the free ions and increased electrical conductivity. © Springer International Publishing Switzerland 2015.


Lysenkov E.A.,Mykolayiv National University Named After Vosukhomlynskiy | Klepko V.V.,Institute of Macromolecular Chemical NAS of Ukraine
Journal of Nano- and Electronic Physics | Year: 2013

The research of the electrical properties of the systems based on polyethylene glycol and carbon nanotubes near-by the percolation threshold is done using the method of impedance spectroscopy. It is established that the percolation threshold for these systems is 0,5%, and critical index t = 1,17. It is discovered that non-conducting polymeric film appears between separate nanotubes. The thickness of the film which is 7-8 Å and its contact resistance which is 3·105 Ohm were derived using theoretical models. This explains a difference in conductivity of pure nanotubes and probed system after the percolation threshold. © 2013.


Lysenkov E.A.,Mykolayiv National University Named After Vosukhomlynskiy | Klepko V.V.,Institute of Macromolecular Chemical NAS of Ukraine | Yakovlev Y.V.,Institute of Macromolecular Chemical NAS of Ukraine
Journal of Nano- and Electronic Physics | Year: 2015

The research of electric properties of the systems based on polyethylene glycol and carbon nanotubes (CNT) near-by the percolation threshold is done using the method of impedance spectroscopy. It is set that the percolation threshold for these systems substantially depends on the sizes of nanotubes. It is discovered that with the increase in the CNT diameter, the percolation threshold is increased. The dispersion parameters of nanotubes were calculated using theoretical model. The results of calculations and microphotographs testify to the high level of CNT{cyrillic} aggregates in the polymer nanocomposites based on polyethylene glycol. © 2015 Sumy State University.


Nychyporenko O.S.,Taras Shevchenko National University | Dmytrenko O.P.,Taras Shevchenko National University | Kylish M.P.,Taras Shevchenko National University | Pinchuk-Rugal T.M.,Taras Shevchenko National University | And 7 more authors.
Problems of Atomic Science and Technology | Year: 2016

Investigation of multiwalled carbon nanotubes (MWCNT) and low density polyethylene nanocomposites with MWCTN morphology were performed using transmission and scanning electron microscopy. Crystalline structure and crystallinity degree was studied for initial nanocomposites and after electron irradiation with diffe rent doses. Changes of Young modulus, electrical conductivity and its dependence on temperature with irradiation dose suggest that at low doses (0.01; 0.02; 0.03 MGy) there polyene sequences are formed within polymer matrix. At higher doses, including 5.0 MGy, these polyene sequences vanish, while intermolecular crosslinks emerge. Such crosslinks significantly influence the temperature dependence of electrical conductivity of nanocomposites containing conductive clusters of nanotubes. It is especially evident after melting temperature. © 2016, National Science Center, Kharkov Institute of Physics and Technology. All rights reserved.

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