{"title":"Effect of CondensednWater at an Alumina/Epoxy ResinnInterface on Curing Reaction","authors":"Satoru Yamamoto (1964233), Yuta Tsuji (1477624), Riichi Kuwahara (2196916), Kazunari Yoshizawa (1415584), Keiji Tanaka (220387)","doi":"10.1021/acs.langmuir.4c01081.s001","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01081.s001","url":null,"abstract":"The adhesion of epoxy adhesives to aluminum materialsnis an importantnissue in assembling parts for lightweight mobility. Aluminum surfacesntypically possess an oxide layer, which readily adsorbs water. Innthis study, the aggregation states of water and its effect on thencuring reaction were examined by placing a water layer between annamorphous alumina surface and a mixture of epoxy and amine components.nThis study used molecular dynamics simulations and density functionalntheory calculations. Before the reaction, water molecules stronglynadsorbed onto the alumina surface, aggregating excess water. Somenwater diffused into the epoxy/amine mixture, accelerating the diffusionnof unreacted substances. This led to faster reaction kinetics, particularlynin proximity to the alumina surface. The adsorption of water moleculesnonto the alumina surface and the aggregation of excess water werensimilarly observed even after the curing process. Subsequently, theninteraction between the alumina surface and various functional groupsnof the epoxy/amine mixture was evaluated before and after the reaction.nEpoxy monomers had little interaction with the alumina surface beforenthe reaction, whereas hydroxy groups formed by the ring-opening reactionnof epoxy groups exhibited notable interaction. Conversely, sulfonylnand amino groups in amine compounds formed hydrogen bonds with OHngroups on the alumina surface before the reaction. However, afternthe reaction, amino groups weakened their interaction with the aluminanOH groups as they transformed from primary to tertiary during thencuring reaction. Both epoxy and amine monomers/fragments similarlyninteracted with water molecules, both before and after the reaction.nThe insights gained from this study are expected to contribute tona better understanding of the impact of moisture absorption on thenapplication of epoxy resins.","PeriodicalId":522810,"journal":{"name":"Figshare","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147904091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}