Dielectric analysis of different natural and synthetic polymer types

Abstract

[Excerpt] Polymers, also called macromolecules, have originated a technological revolution in different technological areas, including automotive and aerospace industries and even electronics, allowing to obtain light, flexible and robust materials with tailored physicochemical properties [1]. Most polymers are dielectric materials and it is possible to tailor specific properties, including electrical, mechanical and thermal properties, for the most technologically demanding application [2]. However, it is essential to understand the dielectric response of polymer material due to the different possible contributions: microscopic fluctuations of the molecular dipoles, propagation of the charge carriers, ions or charge gaps, and charge separation at the various interfaces (Maxwell-Wagner-Sillars contribution) that cause additional polarization contributions [3, 4]. In addition, the relaxation processes in polymer systems are characterized by a distribution of relaxation times that can be described according to various functions based on different empirical models (Debye, Cole-Cole, Cole-Davidson and Havriliak-Negami) allowing to extract a variety of relevant parameters revealing the nature and main characteristics of the observed relaxations [5, 6]. Recently, there is a demand for natural polymers to replace synthetic polymers derived from fossil fuel and, therefore, this chapter will focus on the dielectric response of the most relevant natural polymers after a brief introduction to the dielectric response of the main synthetic polymers. [...]