Catechol-Mediated Glycidylation toward Epoxy Vitrimers/Polymers with Tunable Properties

This work demonstrates a series of epoxy vitrimers/polymers whose properties can be tuned by incorporating a catechol moiety as a part of the starting bisphenol motif. Glycidylation of the catechol containing bisphenol yielded a single-epoxide derivative (E1) and a triepoxide (E3) with tunable ratios through a two-step synthetic approach. El creates a dangling group (benzodioxane) within the network. By comparison, E3 with higher functionality (n = 3) affords networks with improved cross links. By controlling the E1/E3 ratio of epoxy prepolymers, the properties of the resulting vitrimers/polymers can vary significantly. Polymers with the E1/E3 ratio of ca. 6.1 (86:14) exhibited high strain, excellent self-healing properties, and fast stress relaxation that made them readily reconfigurable and could be used as hot-melt adhesives that permitted debonding on demand. Networks with higher content of E3 (e.g., E1/E3 ratio of ca. 0.6 (36:64)), by comparison, exhibited significantly improved thermomechanical properties like tensile strength and modulus.