New Epoxy Thermosets Derived from a Bisimidazolium Ionic Liquid Monomer: An Experimental and Modeling Investigation

Abstract

In this study, a novel polymerizable ionic liquid monomer (ILM) based on a bisimidazolium salt was first synthesized in order to substitute bisphenol A diglycidyl ether (DGEBA) as a starting material, avoiding the use of highly toxic and carcinogenic bisphenol A and epichlorohydrin products. From such a new epoxy monomer, an epoxy network was prepared from the copolymerization between the bisimidazolium salt and isophorone diamine (IPD). Subsequently, the properties of this novel ionic liquid based polymer network have been investigated in terms of polyaddition reaction kinetics as well as the architecture-properties, i.e., thermal stability, surface properties, and the mechanical performances. In addition, for the first time, molecular dynamics simulations were combined with experimental measurements in order to confirm the experimental data as well to be able to predict the physical behaviors from their architecture, molecular scale structuration, and thermomechanical properties of the resulting network. Finally, the substitution of DGEBA by this ILM led to a thermosetting polymer with high thermal stability (up to 450 °C), hydrophobic behavior (21 mJ m–2), and promising mechanical performances (1.7 GPa) including a shape memory behavior.