Polymers

Dielectric properties of liquid-crystal azomethine polymer with a side alkyl-substituted chain, doped with fullerene C$_{60}$

D. S. Kovalev^a, S. V. Kostromin^a, V. Musteaţa^b, V. Cozan^b, S. V. Bronnikov<sup>a

a</sup> Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg
^b Petru Poni Institute of Macromolecular Chemistry, Romanian Academy, Iaşi, Romania

Abstract: We studied the actual and imaginary components of the dielectric constant of liquid-crystal azomethine polymer with a side chain, doped with 0.5 wt % of fullerene C$_{60}$, over a wide range of temperatures and frequencies; measurements were made by means of dielectric spectroscopy. By analyzing the frequency dependence of the dielectric constant, we detected the relaxation processes ($\alpha$, $\beta_{1}$, and $\beta_{2}$) in the nanocomposite, corresponding to certain modes of molecular motion and described them by the Arrhenius equations ($\beta_{1}$- and $\beta_{2}$-processes) and the Vogel–Fulcher–Tamman equation ($\alpha$-process). An antiplasticization effect is discovered after doping the polymer with fullerene C$_{60}$, which manifests itself in increasing the glass transition temperature of the nanocomposite compared to this parameter typical of pure polymer.

Keywords: Dielectric Constant, Fullerene, Liquid Crystal, PMMA, Glass Transition Temperature.

Received: 10.09.2015
Revised: 05.10.2015

 English version: Physics of the Solid State, 2016, 58:4, 835–839

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