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A water-soluble sorbitol polyglycidyl ether (SPE) epoxy monomer was cured with a waterborne polyamine hardener to prepare a fully waterborne epoxy system. Aluminum diethyl phosphinate (AlPi) and melamine cyanurate (MC) flame retardants (FRs) were utilized to develop the flame retardancy of this epoxy matrix. The effect of loading different weights of MC with only 1%P-content from AlPi was discussed to investigate the possible cooperative effect of these two FRs. The best results were obtained at 5% MC loading with 1%P of AlPi as the self-extinguishing behavior was observed with a good limiting oxygen index (LOI). Furthermore, under forced flaming conditions in cone calorimetry measurements, the peak of heat release rate (pHRR) decreased by 27.4%, and the total heat release (THR) decreased by 14.5% compared to the reference epoxy system. This enhancement of flame retardant properties might indicate the synergistic effect between MC and AlPi in a waterborne system. [ABSTRACT FROM AUTHOR]

Summary: Flame‐retarded sorbitol‐based bioepoxy resins cured with cycloaliphatic amine hardener and containing different commercially available additive‐type flame retardants (FRs) have been prepared. Three different oxidation states of phosphorus, aluminium diethyl phosphinate (AlPi) (+1), phosphonate polyol (+3), ethyl ethylene glycol phosphate and ammonium polyphosphate (APP) (+5), have been studied. The effect of using melamine cyanurate with APP and AlPi has been assessed. The self‐extinguishing V‐0 rating according to UL‐94 flammability standard tests and very good limiting oxygen index for combustion are displayed for most flame‐retarded samples at 3 wt% phosphorus content. The flame retardancy effect for the additives was confirmed using cone calorimetry. The samples containing MC with APP at 3%P content showed a dramatic reduction of the total heat release by 60% and reduction of the peak of heat release rate by 70% compared to the reference epoxy matrix. The addition of these FRs together did not decrease the glass transition temperature significantly. [ABSTRACT FROM AUTHOR]