Kinetics of the interfacial curing reaction for an epoxy-amine mixture

• Published in: Physical chemistry chemical physics : PCCP 2022-09, Vol.24 (36), p.21578-21582
• Main Authors: Yamaguchi, Ko, Kawaguchi, Daisuke, Miyata, Noboru, Miyazaki, Tsukasa, Aoki, Hiroyuki, Yamamoto, Satoru, Tanaka, Keiji
• Format: Article
• Language: English
• Subjects: Adhesive strength; Bulk density; Chemical reactions; Curing; Densification; Epoxy phenol novolacs; Molecular dynamics; Quartz; Reaction kinetics
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp03394a

A better understanding of the chemical reaction between epoxy and amine compounds at a solid interface is crucial for the design and fabrication of materials with appropriate adhesive strength. Here, we examined the curing reaction kinetics of epoxy phenol novolac and 4,4′-diaminodiphenyl sulfone at the outermost interface using sum-frequency generation spectroscopy, and X-ray and neutron reflectivity in conjunction with a full atomistic molecular dynamics simulation. The reaction rate constant was much larger at the quartz interface than in the bulk. While the apparent activation energy at the quartz interface obtained from an Arrhenius plot was almost identical to the bulk value, the frequency factor at the quartz interface was greater than that in the bulk. These results could be explained in terms of the densification and orientation of reactants at the interface, facilitating the encounter of the reactants present. A chemical reaction between epoxy and amine compounds at an outermost solid interface was studied by sum-frequency generation spectroscopy, X-ray and neutron reflectivity and a full atomistic molecular dynamics simulation.