Sustainable design of vanillin-based vitrimers using vinylogous urethane chemistry

Abstract

Research on bio-based covalent adaptable networks is popular nowadays in the search for an optimal implementation of thermoset materials and composites in a circular context. Herein, a vanillin derivative is integrated into vitrimers with promising material properties in which the vinylogous urethane associative chemistry has been used as a dynamic covalent chemistry platform. The vanillin derivative, 2-methoxyhydroquinone, is epoxidised and aminated by aqueous ammonia, with the formation of a bi-functional aromatic β-hydroxy-amine. The straightforward synthesis protocol is high yielding and up-scalable, without the need for any chromatographic purification step. The presented rigid, catalyst-free vitrimers have a high renewable carbon content (up to 86%), glass transition temperatures up to 80 °C and show very fast reprocessing and consequently a swift recyclability with relaxation times in the range of seconds by virtue of the applied β-hydroxy-amine functionality. This research thus provides a sustainable approach for the synthesis of vanillin-based vitrimers and fits in with growing interest for the design of recyclable crosslinked polymer materials.