Electrical conductivity and dielectric relaxation studies of biocomposites based on green microcrystalline cellulose-reinforced vinyl resin matrix

Abstract

The dielectric properties of biocomposite materials based on vinyl resin filled with microcrystalline cellulose, in the frequency range from 100 Hz to 1 MHz and in the temperature range from 280 to 400 K, are presented. Two dielectric relaxations were identified. The first one is attributed to the α-relaxation, associated with the glass transition of biocomposite, and the second one, appearing above the glass transition and at low frequencies, was identified as the interfacial polarization effect, which is attributed to the accumulation of charges at the cellulose microcrystalline/matrix interface. Furthermore, the thermal analysis of their relaxation frequency and the electrical conductivity behaviors showed that the activation energy of these composite is more pronounced for the temperatures above the glass transition temperature, suggesting that the interaction between MCC particles and polymeric matrix became significant with the increase of temperature.

Thermal and dielectric properties of carbon nanotubes/graphite/polyester ternary composites

“…To address this concern in the study of interfacial polarization, it was agreed to adopt the formalism of the "electrical modulus", originally initiated by McCrum et al [21]. Macedo et al [22], who used it for the inquiry of electrical relaxation phenomena in glass ionic conductors, and El Bachiri et al [23] used it for analyzing the relaxation process in ferroelectric ceramics. It was also used in polymers and biopolymers to study their relaxation conductivity [24][25][26].…”

“…It was also used in polymers and biopolymers to study their relaxation conductivity. [24][25][26] In this paper, ternary composite materials were prepared by mixing CNT and Gt particles into the polyester matrix. We focus our interest to investigate the influence of the CNT/Gt content on the thermal and dielectric properties of the composites.…”

Maxwell-Wagner-Sillars interfacial polarization in dielectric spectra of composite materials: Scaling laws and applications

“…An interphase is formed, with a linear gradient of local properties between phase A and phase B. The effective dielectric function of the interphase can be calculated by solving the integral shown in equation (16), which leads to…”

“…From an electrical point of view, an interface is an internal surface between two phases having different electrical and dielectric properties. 14 The existence of internal surfaces has a major consequence on the interpretation of the dielectric properties of heterogeneous materials [15][16][17][18][19][20][21][22][23] : the global dielectric response must be now described by at least two different complex dielectric functions, such as for instance, the complex dielectric permittivity function of the phase A (ε * A ¼ ε 0 A À iε 00 A ) and the complex dielectric permittivity function of the phase B (ε * B ¼ ε 0 B À iε 00 B ). If an interphase is formed between the two phases, a third complex dielectric function must be taken into account to describe the dielectric behavior of the 1 system under study (ε * interphase ¼ ε0 interphase À iε 0 0 interphase ).…”

Dielectric properties of microcrystalline cellulose/multi-wall carbon nanotubes multi-scale reinforced EVA/VeoVa terpolymer

“…This behavior is due to faster molecule movements which result in reducing the corresponding relaxation times. 30 The temperature dependence of this latter, determined from the corresponding frequency maximum of derivative loss factor isothermal variation, is presented in Figures 11(a) and (c) for the matrix and its composites VR/MCC/MWCNT0.5 and VR/MCC/MWCNT1, respectively. The obtained tendencies are well described by the VFT law.…”