Coordination and catalysis of Zn²⁺ in epoxy-based vitrimers

Abstract

Network-coordinated Zn2+ ions activate carbonyls, promote alkoxides and hold reactants close to each other for transesterification.

How to Design a Self‐Healing Polymer: General Concepts of Dynamic Covalent Bonds and Their Application for Intrinsic Healable Materials

“…A change of the crosslinking density naturally affects both, T v and T g . A detailed investigation of the catalytic activity of Zn 2+ in the described vitrimers was recently published by Demongeot et al demonstrating a tetrafunctional coordination of zinc(II) by four oxygen atoms of the hydroxyl ester moiety . The general concept of transesterification reactions for self‐healing can be extended to a multitude of polymeric networks.…”

Carbon Nanotubes‐Polyurethane Vitrimer Nanocomposites with the Ability of Surface Welding Controlled by Heat and Near‐Infrared Light

“…Recently, a new class of polymeric materials, known as vitrimer, has attracted increasingly scholars' attention, which bridges the gap between thermosets and thermoplastic materials. Vitrimers are not traditional cross‐linked polymer networks, in which dynamic chemical bonds are introduced, leading to rearrange their topology via thermally triggered exchange reactions without changing the cross‐link density . Thus, dynamic chemical bonds not only realize the reprocessing of thermosetting material but also endow it with some excellent properties, such as multishape memory, healing, and surface welding, which is an amazing breakthrough for welding technology of thermosets.…”

“…Vitrimers are not traditional cross-linked polymer networks, in which dynamic chemical bonds are introduced, leading to rearrange their topology via thermally triggered exchange reactions without changing the cross-link density. [20,21] Thus, dynamic chemical bonds not only realize the reprocessing of thermosetting material but also endow it with some excellent properties, such as multishape memory, healing, and surface welding, [22][23][24][25][26][27][28] which is an amazing breakthrough for welding technology of thermosets. However, most of the vitrimers require some special processing conditions that hindered its practical application during the surface welding in order to get a perfect effect of contact between the surfaces.…”

Ultra‐Fast Microwave Assisted Self‐Healing of Covalent Adaptive Polyurethane Networks with Carbon Nanotubes

“…The cross‐linking bonds of such networks have an associative nature which results in the ability of the material to change its topology via exchange reactions. These reactions are triggered by heat and normally are assisted by the presence of a catalyst; however, multiple catalyst free systems are also developed recently …”

“…The cross-linking bonds of such networks have an associative nature which results in the ability of the material to change its topology via exchange reactions. These reactions are triggered by heat and normally are assisted by the presence of a catalyst; [23] however, multiple catalyst free systems are also developed recently. [16,[24][25][26] Since the pioneering work by Leibler et al [21] on the development of epoxy dynamic networks using transesterification exchange reactions, numerous research have been published to extend the concept to other types of exchange reaction as well as to other polymers.…”