Use of the dielectric analysis to complement previous thermoanalytical studies on the system diglycidyl ether of bisphenol A/1,2 diamine cyclohexane

The dielectric analysis technique was used to characterize an epoxy cured system consisting of a diglycidyl ether of bisphenol A (DGEBA, n=0) and 1,2 diaminecyclohexane (DCH). With this purpose, the permittivity ε′, the loss factor ε″, and the dissipation factor were determined experimentally. The transition observed within the temperature range studied was associated to a α-relaxation process, the T_g of which was taken as that corresponding to the maximum of the ε″−T curve recorded.Argand diagrams for the different temperatures were constructed, and owing to the asymmetry showed by these diagrams, the Havriliak-Negami model was used to analyze data. It was observed that, within the frequency range (0.1-300 Hz) used for this study, the relaxation time follows an Arrhenius behaviour, thus allowing calculation of the activation energy E_a and T_g in good agreement with literature values.