Bio‐ and Water‐Based Reversible Covalent Bonds Containing Polymers (Vitrimers) and Their Relevance to Adhesives – A Critical Review

A new class of materials, reversible covalent bonds containing polymers (RCBPs), are introduced under the category of thermosetting materials. RCBPs are made of reversible covalent bonds, such as DA (Diels-Adler), acylhydrazone, imine, β-hydroxy ester, or disulfide bonds, and thus provide remarkable properties. These bonds render the materials thermally processable, meaning they fall into the domain of thermoplastic rheology (unlike "regular" thermosets), and thus possess a great potential in the field of debonding-on-demand adhesives. This review attempts to further investigate the emerging field of RCBPs, focusing on the chemical origins of polymers and the use of renewable resources instead of petroleum-based ones. Additionally, we also review water-based systems to advance the environmental agenda by reducing the use of toxic or hazarded solvents. This review presents RCBP materials predominantly from renewable resources, either bio- or water-based or a combination of both. One of the main subjects presented are hydrogels from bio- and water-based systems. Moreover, this article provides detailed properties and applications of such materials and suggests possible further investigations.