Preparation of Colorless, Highly Transparent, Epoxy-Based Vitrimers by the Thiol-Epoxy Click Reaction and Evaluation of Their Shape-Memory Properties

Abstract

Vitrimers are functional cross-linked materials with an associative bond-exchange mechanism. Here, we demonstrate the preparation of colorless and highly transparent epoxy-based vitrimers by using a simple reaction of commercially available, thiol-functionalized, and epoxy-functionalized monomers, that is, trimethylolpropane tris­(3-mercaptopropionate) (Tri-SH) and bisphenol A diglycidyl ether (di-epoxy), which can thus contribute to the practical application of vitrimers because conventional vitrimers, especially epoxy-based vitrimers, suffered from a yellowish color and poor transparency. The present preparation includes another advantage of the efficient progress of the cross-linking reaction under relatively mild and quick reaction conditions (120 °C, 2 h) in comparison with the reported epoxy-based vitrimers, owing to the “click” nature of the thiol–epoxy reaction. Because the T g evaluated by differential scanning calorimetry is close to room temperature, the obtained vitrimer shows a Young’s modulus comparable to glassy polymers and also ductile tensile property, which is another advantage in terms of mechanical properties. Vitrimeric properties, such as the softening temperature and stress relaxation, are first evaluated, and the unique shape-memory property with a shape-editable function owing to the capability of network topology alternation is also demonstrated.

Dominant Factor of Bond-Exchange Rate for Catalyst-Free Polyester Vitrimers with Internal Tertiary Amine Moieties

“…Since the pioneering series of vitrimer studies reported by Leibler’s group, various designs of vitrimers have been developed using different bond-exchange reactions. Polyester-based vitrimers with a bond-exchange mechanism via trans-esterification is one of the most reported designs for vitrimer preparation. ,− Trans-esterification is the reaction to exchange ester and alcohol moieties, which usually operates in the presence of catalysts. Polyester vitrimers can thus be prepared by designing networks bearing ester bonds and OH groups with addition of a trans-esterification catalyst.…”

An editable shape-memory transparent wood for smart building materials

“…2b, the characteristic monomer peak, epoxy peak (910 cm -1 ) in E51, and thiol peak (2566 cm -1 ) in Tetra-SH disappeared in the spectra of the vitrimers, while the hydroxyl peak (3200-3600 cm -1 ) appeared. 40,41 The FT-IR spectra of the vitrimers and ESMTW samples exhibited high similarity, indicating that a high content of vitrimers filled the porous structures of the DW scaffold. The density of the ESMTW was approximately 1.232 g cm -3 .…”

Enhanced photodegradation of TiO2‐containing poly(ε‐caprolactone)/poly(lactic acid) blends

“…Recently, Christensen et al achieved closed loop recycling of a crosslinked thermoset by utilizing acid‐degradable diketoenamine bonds whereby they could isolate the triketone monomers such that the network reformed with nearly identical properties 8 . Likewise, the seminal work of Montarnal et al, who first reported on vitrimers, has inspired many research groups around the world, each developing ever so compelling chemistry to achieve these unique reprocessable networks 9–24 …”

“…8 Likewise, the seminal work of Montarnal et al, who first reported on vitrimers, has inspired many research groups around the world, each developing ever so compelling chemistry to achieve these unique reprocessable networks. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Unfortunately, many of the strategies highlighted above can prove costly with sometimes exotic and hardto-scale chemistry and often rely upon the collection of waste for further processing or composting in controlled environments. Dishearteningly, a staggering 32% of polymer-based waste escapes that very collection system and the convenience (and sometimes necessity of singleuse plastics as seen during the COVID-19 pandemic) comes in the way of ecological considerations.…”