Issue 12, 2016

Sequential curing of off-stoichiometric thiol–epoxy thermosets with a custom-tailored structure

Abstract

A new dual-curing system based on sequential thiol–epoxy click polycondensation and epoxy anionic homopolymerization was studied. Formulations of diglycidyl ether of bisphenol A and trimethylolpropane tris(3-mercaptopropionate) with 1-methylimidazole as a base catalyst and excess of epoxy groups were prepared and characterized. The curing process is sequential: fast thiol–epoxy polycondensation takes place first, followed by slower homopolymerization of excess epoxy groups. This makes it possible to define curing sequences with easy time–temperature control for both curing stages. The network build-up process during the first curing stage can be easily modelled assuming ideal polycondensation, which allows tailoring the structure and properties of the intermediate materials. The homopolymerization of the excess epoxy groups in the second curing stage results in a higher glass transition temperature (Tg) in comparison with the stoichiometric thiol–epoxy material, thus extending the application of thiol–epoxy thermosets to wider temperature ranges.

Graphical abstract: Sequential curing of off-stoichiometric thiol–epoxy thermosets with a custom-tailored structure

Supplementary files

Article information

Article type
Paper
Submitted
19 Jan 2016
Accepted
25 Feb 2016
First published
26 Feb 2016
This article is Open Access
Creative Commons BY license

Polym. Chem., 2016,7, 2280-2290

Sequential curing of off-stoichiometric thiol–epoxy thermosets with a custom-tailored structure

X. Fernández-Francos, A. Konuray, A. Belmonte, S. De la Flor, À. Serra and X. Ramis, Polym. Chem., 2016, 7, 2280 DOI: 10.1039/C6PY00099A

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