Characterization of Sequential Trial‐Curable Off‐Stoichiometric Amine‐Epoxy Thermosets with Ionic Liquids

This work aims to develop sequential trial‐curable off‐stoichiometric thermosets, patterning the approach upon the dual‐curing processing, which is a promising method to tailor material properties by combining two polymerization reactions. The presented epoxy resin systems are based on diglycidyl ether of bisphenol A (DG) as an epoxy resin, Gaskamine 240 (G) as a low‐temperature amine curing agent, and 1‐ethyl‐3‐methylimidazolium dicyanamide (IL) as an ionic liquid, which is known by its potential efficient latency. Therefore, three curing polymerization reactions take place, in contrast to common dual‐curable formulations. In this study, the target is to still separate the first curing process – which is the epoxy‐amine condensation reaction – from the remaining two curing processes, which are triggered by IL. The trial‐curable systems offer the possibility to achieve different intermediate materials, from highly viscous through shape‐conformable to rigid. This is attained by changing the relative contribution of the first and the other two curing steps, e.g. the change in the amount of G. Another motivation to use IL is to enhance the glass transition temperature of final samples; the values are between 84.4 and 152.2 °C.