Latent curing of epoxy-thiol thermosets
Epoxy-thiol curing is a click reaction which allows quantitative yield of the end products. The base-catalyzed reaction is rapid at low temperatures so it is most often desirable to harness reactivity by using latent catalysts. In this work, we used triazabicyclodecene tetraphenylborate (TBD·HBPh4)...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/103949 |
| Acceso en línea: | https://hdl.handle.net/2117/103949 https://dx.doi.org/10.1016/j.polymer.2017.03.064 |
| Access Level: | acceso abierto |
| Palabra clave: | Chemical kinetics Epoxy-thiol Click reaction Curing kinetics Photobase Latency Cinètica química Àrees temàtiques de la UPC::Enginyeria química::Química física::Cinètica |
| Sumario: | Epoxy-thiol curing is a click reaction which allows quantitative yield of the end products. The base-catalyzed reaction is rapid at low temperatures so it is most often desirable to harness reactivity by using latent catalysts. In this work, we used triazabicyclodecene tetraphenylborate (TBD·HBPh4) as a photobase generator (PB). We activated the PB either thermally or by UV light and monitored reaction kinetics by DSC and FTIR methods. Depending on the catalytic system used, the rate of the thiol-epoxy reaction was ordered as follows: Neat base > UV activated PB > thermally activated PB > uncatalyzed system. A series of isothermal and non-isothermal DSC experiments were run on non-irradiated and irradiated samples in order to study the effect of PB content and UV irradiation duration on PB activation efficiency and latency/storage stability. The data from DSC were analyzed using model-free linear isoconversional methods to estimate kinetic parameters such as activation energies. In addition, the kinetics data for both activation methods were shown to be accurately represented by multi-term Kamal models. The storage stability of the systems were studied at room temperature and was shown to fit well to the predictions of the kinetic model. |
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