Abstract
Two polymers were prepared from diglycidyl ether of bisphenol A (DGEBA) and triglycidyl p-aminophenol (TGAP) epoxy resins, using the same hardener diethylenetriamine (DETA). The obtained polymers were compared in terms of structural, optical, mechanical, thermal and dielectric properties. Dielectric spectroscopy and dynamic mechanical analysis indicated the presence of dipolar dielectric relaxations in both polymers, and interfacial one only for TGAP/DETA, which is consistent with XRD findings. Different approaches were considered to fit electrical modulus and conductivity and to estimate the relaxation times and activation energies according to temperature. For optical measures, a novel result processing approach is proposed for an accurate determination of the polymers bandgap and for highlighting the existence of additional energy transition level for TGAP. Results indicate that this polymer could be a potential candidate for use as a protective film and as UV/blue-light filter for screens and windows.
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•Rational method discriminating between direct and indirect optical bandgaps.•Absorption in the violet-bleu ascribed to the existence of energy levels in the gap.•Possible use of TGAP polymer as screen/window protective film and blue-light filter.•Enhancement of conductivity of more than two orders of magnitude.•Arrhenius and VFT modeling for characterizing thermally activated relaxations.