The traditional intumescent flame retardant is composed of acid source ammonium polyphosphate (APP),carbon source pentaerythritol (PER)and gas source melamine (MEL)at the mass ratio of 3 ∶ 1 ∶ 1. Biomass-tannic acid (TA)was used as a green intumescent flame retardant in epoxy resin instead of PER with APP and MEL. The effects of different ratios of acid source APP,new carbon source TA and gas source MEL on the flame retardancy and mechanical properties of epoxy resin (EP)composites were investigated. The experimental results showed that when the addition of the new intumescent flame retardant was 20wt% and the mass ratio of APP ∶ TA ∶ MEL was 9. 71 ∶ 6. 11 ∶ 3. 68, the LOI value of the obtained flame retardant EP-3 composites increased to 38. 80% and the UL-94 test reached V-0 level. Cone calorimetric tests showed that the peak heat release rate (PHRR),total heat release (THR),total smoke generation (TSP)and average carbon monoxide release rate (av-CO)of EP-3 decreased by 48. 96%,14. 33%,26. 83% and 28. 01%,respectively,compared with those of EP-0 added conventional intumescent flame retardants,which indicated that APP / TA / MEL green flame retardants had excellent synergistic flame retardant effect. Moreover,the TG,DTG and SEM analysis revealed that the flame retardant mechanism was a synergistic mechanism of gas phase and solid phase flame retardant. In particular,the flame retardant promoted the formation of the carbon layer with high density and strength of the substrate,thus greatly improving the solid phase flame retardant effect. In addition,the mechanical property test showed that the new carbon source TA was beneficial to improve the tensile strength and flexural strength of the flame retardant EP composites. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.
