Epoxy-Rich Systems with Preference for Etherification over Amine-Epoxy Reactions for Tertiary Amine Accelerators
نویسندگان
چکیده
Epoxies are often cured using primary and secondary amines in an efficient reaction catalyzed by tertiary amines. Through coordination effects, lower the transition-state energy enough to allow take place under ambient conditions. In this paper, we demonstrate how, conditions, bound close intramolecular proximity a amine able catalyze amine-epoxy reactions as well promote etherifications epoxy-rich systems. 13C nuclear magnetic resonance (NMR) was used identify sequence of curing model benzyl glycidyl ether (BGE) with 3-diethylaminopropylamine (DEAPA), 3-dimethylaminopropylamine (DMAPA), hexylamine, respectively. The results clearly show that DMAPA favors etherification over reactions, while DEAPA displays expected trend toward reactions. This experiment repeated for epoxy system based on bisphenol A diglycidylether (BADGE) same three amines, differential scanning calorimetry (DSC) confirmed preference via quantification exotherms. Finally, novel DMA setup corroborated observed rate each catalyst measuring gelation time vitrification during isothermal curing.
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ژورنال
عنوان ژورنال: Macromolecules
سال: 2021
ISSN: ['0024-9297', '1520-5835']
DOI: https://doi.org/10.1021/acs.macromol.0c02630