Effect of Hydroxyl Mobility on the Cure Kinetics of Diglycidyl Ether of Bisphenol A (DGEBA) Epoxy in the Presence of a Tertiary Amine

Previous work on curing a DGEBA epoxy with diethanolamine (DEA) has highlighted the complexity of the reaction. This involves a rapid secondary amine, adduct forming reaction followed by a slower anionic polymerization, crosslinking reaction. This second reaction is activated by the tertiary amine created in the adduct and is strongly influenced by the alcohol groups in the DEA. In the present study, dibutylamine (DBA) and octanol were employed instead of DEA. The octanol hydroxyls are more mobile than the DEA hydroxyls. The epoxide to amine ratio was kept constant while the hydroxyl concentration was varied by changing the amount of octanol added. A non-reactive alkane was used to control the reactive group concentrations in both the DEA and DBA mixtures. Isothermal cures are performed on an air cooled thermal activity monitor (TAMAir) for varying DBA/Octanol/alkane ratios and temperatures. Distinctive kinetic signatures are found for the different reactive mixtures.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.