To address the inherent flammability and processability issues of epoxy resins while maintaining their glass transition temperature (Tg) and mechanical strength, epoxy-terminated linear flame retardants (ETLFRs) were developed using vanillin-based bio-epoxy materials. ETLFRs were synthesized from renewable sources, specifically vanillin and guaiacol, and their chemical structures were comprehensively characterized via NMR and FTIR analyses. The synthesized ETLFR was blended with N, N-diglycidyl-4-glycidyloxyaniline and cured using 4,4'-diaminodiphenylmethane (DDM). The cured systems were systematically evaluated for thermal stability, mechanical properties, flame retardancy, and compatibility. Results showed that the incorporation of ETLFR markedly enhanced the fire resistance of the epoxy network, achieving a UL-94 V-0 rating at a 20 wt% loading with only 0.30 wt% phosphorus content. Additionally, the inherent branch rigidity of ETLFR contributed to improved mechanical performance. The developed flame-retardant bio-based epoxy systems show promising potential for advanced applications in electronics, automotive, aerospace, and defence industries.
Gupta et al. (Wed,) studied this question.