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Protonation of Strained Epoxy Resin under Wet Conditions via First-Principles Calculations Using the H + -Shift Method.
- Source :
-
The journal of physical chemistry. B [J Phys Chem B] 2023 Mar 23; Vol. 127 (11), pp. 2629-2638. Date of Electronic Publication: 2023 Mar 14. - Publication Year :
- 2023
-
Abstract
- A significant challenge in adhesive bonding is the accelerated breaking of stretched adhesives under wet conditions, which is known as cohesive failure. One group of commonly used adhesives consists of the amine-cured epoxy resins. Based on deprotonation free-energy calculations of the unstrained resin in water, it has recently been proposed that these adhesives can undergo failure through breakage originating at the protonated amine group under neutral or acidic conditions [ J. Phys. Chem. B 2021 , 125 , 8989-8996]. In this study, we comprehensively investigated the degree of protonation of the amine group under both stretched and compressed conditions by devising a robust first-principles protonation calculation method applicable to strained materials. It was found that the amine group was partially protonated in neutral water at 298 K and that the amine group was protonated when the epoxy resin was stretched to a greater extent in water, and vice versa. These findings support the physicochemical cause of cohesive failure due to protonation of the amine group in the stretched amine-cured epoxy resins.
Details
- Language :
- English
- ISSN :
- 1520-5207
- Volume :
- 127
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry. B
- Publication Type :
- Academic Journal
- Accession number :
- 36917503
- Full Text :
- https://doi.org/10.1021/acs.jpcb.3c00401