Effects of curing agent on conductivity, structural and dielectric properties of an epoxy polymer

•Two epoxy polymers were prepared by curing (DGEBA) with (EDA) and the (33′DDS).•X-ray data reveal the presence of a locally periodic nanostructure in DGEBA/33′DDS.•γ and α dipolar relaxations were highlighted for the two polymers.•Maxwell Wagner Sillars (MWS) relaxation appears only in the DGEBA/33′DDS.•DGEBA/EDA is more conductive than the DGEBA/33′DDS.

Two epoxy polymers were prepared by curing the diglycidyl ether of bisphenol A (DGEBA) epoxy resin with two hardeners: the ethylenediamine (EDA) and the 3,3′-diaminodiphenyl sulfone (33′DDS) which are respectively aliphatic and aromatic. Structural properties of DGEBA/EDA and DGEBA/33′DDS polymers were investigated by means of grazing incidence X-ray reflectometry. Their dielectric properties were studied using the dielectric relaxation spectroscopy (DRS) over wide ranges of temperature (from −80 to 200 °C) and frequency (from 10−1-106 Hz), and thermally stimulated depolarization current (TSDC) technique. X-ray data revealed the presence of a locally periodic nanostructure in polymer cured with the aromatic hardener (DGEBA/33′DDS). γ and α dipolar relaxations were highlighted for the two polymers while the Maxwell-Wagner-Sillars (MWS) relaxation appears only in the DGEBA/33′DDS. The electric modulus data were fitted using Havriliak-Negami approch. Conductive properties of epoxies were investigated. Ac conductivity data reveal that DGEBA/EDA is more conductive than the DGEBA/33′DDS.

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