Fuente: Journal of applied polymer Lugar: REVIEW Epoxy resins, despite their wide applicability, are limited by flammability. Chemists are exploring flame retardants (FRs), with Schiff base chemistry emerging as a promising method due to its effective char-forming ability. The imine group enhances flame resistance by enabling crosslinked, nitrogen-rich networks. This review discusses approaches to synthesize FRs for epoxy resins using Schiff base chemistry.


ABSTRACT
Epoxy resins are a widely used polymeric material for a wide range of applications. Nevertheless, the intrinsic flammable nature of epoxy resins limits their applications in extreme conditions. Chemists look for suitable flame-retardants (FRs) to impart flame retardance to the epoxy resin. Adapting suitable organic synthetic approaches to synthesize FRs is always viable. Schiff base chemistry has emerged as a promising approach for developing FRs in epoxy resins, mainly due to its efficient char-forming ability. The imine group (CN) not only serves as a functional site for attaching FR agents like DOPO, but also contributes to flame retardance in the condensed phase by facilitating the formation of cross-linked, nitrogen-containing cyclic networks between Schiff base units. The present review provides an overview of possible approaches to make FRs for epoxy resins via Schiff base chemistries. The flame-retardant mechanism of Schiff base-containing epoxy thermosets is also proposed. Significant findings from multiple research groups, as well as major insights and viewpoints, are discussed.