At present, numerous researchers are focused on polyimide (PI) modifications that should lead to extension of potential PI application areas. This paper presents the effects of certain modifications of PI on dielectric relaxations process in the PI films. Modyfication of PI were carried by addition of some amount of fullerene nanoparticles (0.1-2.0 % wt) in polyamidoacids of different structures with subsequent thermal polycyclization of obtained compositions.
The essential differences in relaxation were observed in low frequency range and high temperature range. So far, as in PI composites, the relatively steady dipole structure of activation energy at 0,1 eV can be observed, the addition of fullerens induces charge relaxation. Its the time constants and activation energies depend on the amount of C ₆₀. In that case a wide extent of changes in activation energy values ranging from 0,45 eV up to 1,6 eV is particularly noticeable.
Another effect of C ₆₀ presence is an evident decrease in dielectric permitivity ε _r for the entire range of temperatures applied and decrease in dielectric loss factor tan δ for the temperatures lower than 300 K. A constant temperature of extrema tan δ and a decrease in their values along with higher fullerene contents can indicate that the additions of C ₆₀ do not generate qualitative changes in main dipole relaxation of time constant τ ₁, however they cause the main dipole relaxation volume reduction. It can indicate that first, the dipole relaxations fill free spaces in the nanoparticles-PI composites whereas the space charge is likely to be formed at the phase boundary between the main PI chain and the fullerene.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/542 must be provided.