Dielectric properties of nanocomposites based on cellulose nanocrystals (CNCs) and poly(styrene-co-2-ethyl hexylacrylate) copolymer

Publication date: 8 September 2017
Source:Polymer, Volume 125
Author(s): A. Ladhar, A. Ben Mabrouk, M. Arous, S. Boufi, A. Kallel
In the present work, the dielectric properties of nanocomposites based on poly(styrene-Co-2-ethyl hexylacrylate) copolymer (StHA) and cellulose nanocrystals (CNCs) and γ-methacryloxypropyl triethoxysilane (MPS) as a coupling agent were investigated. Four relaxation processes were detected: the β relaxation, the α relaxation, the electrode polarization and the ionic conduction phenomenon. These two later were identified with the real part ε' and the imaginary part ε" of the dielectric permittivity slopes. Moreover, the electrode polarization was spotted using the first derivative of the real part of the dielectric permittivity. The activation energy EA for the β relaxation, the strength parameter D for the α relaxation and the relaxation strength Δε showed a threshold value of 4% in weight of CNC. Variations were explained with attractive and repulsive cellulose-cellulose and cellulose-copolymer interactions. The electrical study confirmed the dielectric results indicating the higher conductivity for the nanocomposite with 4%w.t of CNC. This work provided additional evidence of the formation of a rigid percolation network via hydrogen bonding for nanocomposites based on CNCs.

Graphical abstract

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