Review on intrinsically recyclable flame retardant thermosets enabled through covalent bonds

Abstract

Developing thermosets with inherent recyclability and flame retardancy is a great importance from the views of fire safety, resource conservation and environmental protection. Owing to their superior mechanical properties, versatility, outstanding adhesion-ability, durability, thermal, and solvent stability comparable to conventional thermosets while demonstrating end-of-life reuse, recyclable thermosetting materials have gained much interest as an attractive class of sustainable thermosets. The chemical structure of thermosets includes dynamic covalent networks that provide durability and reprocessability. However, these recyclable thermosets possess significant flammability, limiting their application in automobiles, railways, aircraft, buildings, and electronic items. Thus, it is urgent to include them with flame retardants. The goal of this review paper is to give a broad understanding of the study by highlighting and discussing recent advances as well as future prospects for inherently recyclable flame retardant thermosets (RFRs). Moreover, synthesis methods have been highlighted to improve the design of internally recyclable fire retardant thermosets. A distinct emphasis will be given on the inherent RFRs in terms of flame retardancy, recycling property, physical properties, and thermal stability. Finally, we will explore the importance and threats that intrinsically recyclable flame retardant thermosets face in the future.