Crown ethers as new curing agents for epoxy resins |
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| Authors: | Francisco Fraga López Eva C Vázquez Barreiro Aida Jover José Manuel Martínez Ageitos Eugenio Rodríguez José Vázquez Tato |
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| Affiliation: | Facultad de Ciencias, Departamentos de Física Aplicada y Química Física, Campus de Lugo, Universidad de Santiago de Compostela, Spain |
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| Abstract: | Different crown ethers (4‐aminobenzo‐15‐crown‐5 (4‐aminobenzo‐15‐C5), 1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane (diaza‐18‐crown‐6), tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (H4DOTA) and tetraazacyclododecane‐1,4,7,10‐tetraacetamide (H2ODDA)) were used as curing agent for bisphenol A diglycidyl ether (BADGE, n = 0). The maximum enthalpy change for all systems except that formed by the epoxy resin with H4DOTA corresponds to a stoichiometric ratio, since from this value the reaction enthalpies decrease when the proportion of epoxy increases. Heteropolymerization reaction occurs in all the crown ethers. Etherification reactions occur at temperatures much lower (30 °C less) than for the porphyrin systems studied in which a second signal appears at 300 °C. The etherification is evidenced by a slight shoulder in the thermograms for H4DOTA and H2ODDA. The systems BADGE (n = 0)/4‐aminobenzo‐15‐C5 and BADGE (n = 0)/diaza‐18‐crown‐6 improve the thermal stability of the epoxy resin by 30 °C approximately while the improvement for BADGE (n = 0)/H4DOTA and BADGE (n = 0)/H2ODDA is about 60 °C. © 2017 Society of Chemical Industry |
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| Keywords: | crown ethers epoxy resin etherification esterification |
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