Dielectric study of a cyclo-aliphatic UV-curable epoxy resin copolymerized with a low glass transition co-monomer bearing methylene units

This work focuses on dielectric properties of a polymer constituted of epoxy resin and a very low glass transition temperature polymer. To this aim, a cycloaliphatic diepoxy monomer, namely 3, 4 - epoxycyclohexylmethyl-3´, 4´ - epoxy-cyclohexane carboxylate (CE), was copolymerized with 1,6-hexanediol diglycidyl ether (HDGE) by UV-curing employing different CE amounts (up to 40 wt. %). Two relaxation modes namely β and γ were observed, attributed to the local molecular motions. It has been shown that the dielectric constant and the thermal properties depend on the concentration of the CE. Their structural morphology and the effect of space charge were studied using the Thermal Step Method. The dielectric responses for UV-cured HDGE/CE systems are presented. The potential effect of moisture and/or ions, the effect of the formation of a polymer network having a tunable crosslinking density and the effect of space charge on the copolymers were also investigated. The influence of chain lengths on dielectric behaviour has also been investigated.