A comparative study of structural and dielectric properties of diglycidyl ether of bisphenol A (DGEBA) cured with aromatic or aliphatic hardeners

作者：Jilani Wissal^*; Mzabi Nissaf; Fourati Najla; Zerrouki Chouki; Gallot Lavallee Olivier; Zerrouki Rachida; Guermazi Hajer

来源：Journal of Materials Science, 2016, 51(17): 7874-7886.

DOI：10.1007/s10853-016-0043-0

This study aims to present structural and dielectric comparisons between two epoxy polymers. These polymers are realized by curing diglycidyl ether of bisphenol A (DGEBA) resin with either aliphatic 1,3-diaminopropane (PDA) or aromatic 4,4'-diaminodiphenyl sulfone (DDS) hardeners. They are called DGEBA/PDA and DGEBA/DDS. Several complementary techniques have been used in the present study. The structural analysis was performed using grazing incidence X-ray reflectometry. It reveals the presence of a locally ordered nanostructure in the DGEBA/DDS polymer and an amorphous character for the DGEBA/PDA one. Dielectric characterization was carried by means of dielectric relaxation spectroscopy (DRS), thermally stimulated depolarization current (TSDC) and time domain spectroscopy (TDS). DRS measurements performed over wide ranges of temperature (-80 to 160 degrees C) and frequency (10(-1)-10(6) Hz) showed the presence of dipolar gamma and alpha relaxations in both polymers. Nevertheless, the interfacial Maxwell-Wagner-Sillars (MWS) relaxation appeared only in DGEBA/DDS. This can be related to the local nanostructure within this polymer, which can give rise to interfaces. Relaxation parameters were deduced from the best fits of experimental data with the Havriliak-Negami model. The calculated fragility index indicates that DGEBA/DDS is more fragile than DGEBA/PDA. The loss factor epsilon ''(f) was calculated from the isothermal discharging current measurements, using Hamon approximation. Thanks to this epsilon '' calculation an interfacial relaxation was revealed in the frequency range of 10(-3)-10(-1) Hz for each investigated polymer.

• 出版日期2016-9