{"title":"Novel Thermal Latent Curing Agents for Epoxy Resins Based on Dual-Locked Aminopyridines by Amidation and N-Oxidation","authors":"Yukai Ito, Daisuke Aoki, Koji Arimitsu","doi":"10.1021/acs.macromol.4c02707","DOIUrl":null,"url":null,"abstract":"Thermal latent curing agents are very important industrially because they can cure epoxy resins at a set temperature and can be stored as one-component systems. However, it remains difficult to achieve both a long pot life and high reaction efficiency. Herein, we present a dual-locked thermal latent curing agent based on aminopyridines, protected by amidation and <i>N</i>-oxidation, designed to enhance both pot life and final curing efficiency. We demonstrated that this dual-locked aminopyridine undergoes stepwise deprotection during the epoxy curing process, as evidenced by <sup>1</sup>H NMR and MALDI-TOF MS analyses of model epoxy polymerizations. The curing temperature of epoxy resin with the dual-locked aminopyridines was modifiable within the range 120–154 °C, influenced by the electron density on the <i>N</i>-oxide. Furthermore, the dual-lock strategy was found to significantly improve the storage stability of one-component epoxy resins and promote the curing of epoxy with high efficiency compared to unprotected aminopyridines.","PeriodicalId":51,"journal":{"name":"Macromolecules","volume":"27 1","pages":""},"PeriodicalIF":5.1000,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Macromolecules","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.macromol.4c02707","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Thermal latent curing agents are very important industrially because they can cure epoxy resins at a set temperature and can be stored as one-component systems. However, it remains difficult to achieve both a long pot life and high reaction efficiency. Herein, we present a dual-locked thermal latent curing agent based on aminopyridines, protected by amidation and N-oxidation, designed to enhance both pot life and final curing efficiency. We demonstrated that this dual-locked aminopyridine undergoes stepwise deprotection during the epoxy curing process, as evidenced by 1H NMR and MALDI-TOF MS analyses of model epoxy polymerizations. The curing temperature of epoxy resin with the dual-locked aminopyridines was modifiable within the range 120–154 °C, influenced by the electron density on the N-oxide. Furthermore, the dual-lock strategy was found to significantly improve the storage stability of one-component epoxy resins and promote the curing of epoxy with high efficiency compared to unprotected aminopyridines.
期刊介绍:
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.