Segregated carbon nanotube networks in CNT-polymer nanocomposites for higher electrical conductivity and dielectric permittivity, and lower percolation threshold

TY - JOUR

T1 - Segregated carbon nanotube networks in CNT-polymer nanocomposites for higher electrical conductivity and dielectric permittivity, and lower percolation threshold

AU - Du, Han

AU - Fang, Chao

AU - Zhang, Juanjuan

AU - Xia, Xiaodong

AU - Weng, George J.

N1 - Publisher Copyright: © 2022

PY - 2022/3/1

Y1 - 2022/3/1

N2 - In an effort to find higher electrical properties of CNT-based polymer composites, a segregated CNT (carbon nanotube) network model is constructed, and a computational scheme is also provided. The construction involves randomly oriented CNTs decorated on the surface of polymer particles. A two-scale computational scheme with segregated CNT networks as the small scale and the overall composite consisting of polymer particles and segregated networks as the large scale is proposed. The small-scale problem involves percolation feature and is solved through Bruggeman's effective-medium approximation, while the large-scale problem is solved with Hashin's exact approach in conjunction with the small-scale solution. The formulations are further extended to the complex domain for the analysis of frequency dependence under AC loading. In this process, the influence of interphase, electron tunneling, Maxwell-Wagner-Sillars polarization, Dyre's electron hopping, and Debye's dielectric relaxation, are also incorporated. The calculated results are validated with experimental data of 2-phase CNT/PA (polyamide) and 3-phase CNT/PA/PP (polypropylene) nanocomposites. Compared with homogeneously dispersed CNT systems, it is also demonstrated that segregated CNT networks can indeed lead to markedly higher conductivity and permittivity, and lower percolation threshold.

AB - In an effort to find higher electrical properties of CNT-based polymer composites, a segregated CNT (carbon nanotube) network model is constructed, and a computational scheme is also provided. The construction involves randomly oriented CNTs decorated on the surface of polymer particles. A two-scale computational scheme with segregated CNT networks as the small scale and the overall composite consisting of polymer particles and segregated networks as the large scale is proposed. The small-scale problem involves percolation feature and is solved through Bruggeman's effective-medium approximation, while the large-scale problem is solved with Hashin's exact approach in conjunction with the small-scale solution. The formulations are further extended to the complex domain for the analysis of frequency dependence under AC loading. In this process, the influence of interphase, electron tunneling, Maxwell-Wagner-Sillars polarization, Dyre's electron hopping, and Debye's dielectric relaxation, are also incorporated. The calculated results are validated with experimental data of 2-phase CNT/PA (polyamide) and 3-phase CNT/PA/PP (polypropylene) nanocomposites. Compared with homogeneously dispersed CNT systems, it is also demonstrated that segregated CNT networks can indeed lead to markedly higher conductivity and permittivity, and lower percolation threshold.

KW - AC frequency

KW - CNT/polymer nanocomposites

KW - Coated hexagonal inclusions

KW - Electrical conductivity, permittivity and percolation threshold

KW - Segregated CNT networks

UR - https://www.scopus.com/pages/publications/85124517969

UR - https://www.scopus.com/pages/publications/85124517969#tab=citedBy

U2 - 10.1016/j.ijengsci.2022.103650

DO - 10.1016/j.ijengsci.2022.103650

M3 - Article

SN - 0020-7225

VL - 173

JO - International Journal of Engineering Science

JF - International Journal of Engineering Science

M1 - 103650

ER -