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Epoxy resin (EP) has been widely used in coatings, adhesives, and composites. However, EP is flammable with severe smoke production. The addition of flame retardant fillers into EP can effectively improve its flame retardancy, but often brings mechanical reduction to EP. Herein, a high‐effective boron‐containing flame‐retardant (2‐phenyl‐1,3,2‐dioxaborolan‐4‐yl) methanamine ammonium polyphosphate (PBMA‐APP) is synthesized and introduced into EP to improve the fire resistance and the impact toughness. With the addition of 6% PBMA‐APP, the fire performance of EP is significantly improved. The Underwriters Laboratories‐94 rating is increased to V‐0, the total heat release and total smoke production (TSP) are reduced by 30% and 32%, respectively. It is proposed that the synergistic effect among B, N, and P in PBMA‐APP promoted the char formation of EP. The addition of 6% PBMA‐APP into EP causes little effect on tensile strength but increases the impact strength of EP to 11.2 kJ m−2. This work has proposed a possible strategy to develop a high‐efficient flame retardant for thermosetting resins. [ABSTRACT FROM AUTHOR]

A unique mono-component intumescent flame retardant, named PPy-MAPP, of which melamine-coated ammonium polyphosphate (MAPP) was microencapsulated by polypyrrole (PPy), was synthesized and carefully characterized. The obtained PPy-MAPP was applied to epoxy resin (EP) for obtaining flame-retarded EP composites. The results show that PPy-MAPP imparts better flame retardancy and smoke suppression properties to EP compared to the same addition of MAPP. The EP composite with 15 wt% PPy-MAPP easily passes the UL94 V-0 rating and achieves an LOI value of 42.4%, accompanied by a 61.9% reduction in total heat release (THR) and a 73.9% reduction in total smoke production (TSP) when compared with pure EP. The char residue analysis shows that PPy-MAPP can promote a generation of more phosphorus-rich structures in the condensed phase that improve the integrity and intumescence of char against fire. The mechanical test indicates that PPy-MAPP has a less negative effect on the tensile strength and elastic modulus of epoxy resin due to the good compatibility between PPy-MAPP and the EP matrix, as supported by differential scanning calorimetry (DSC) analyses. In this paper, these attractive features of PPy-MAPP provide a new strategy to prepare satisfactory flame retardant and super flame retarding EP composites. [ABSTRACT FROM AUTHOR]

A novel diaminodiphenylmethane (DDM) modified ammonium polyphosphate (APP) flame retardant, DDP, was successfully synthesized via ion-exchange reaction. DDP was introduced into epoxy resins (EPs) to reduce flammability. A comparable level of DDP exerts better flame-retardant and smoke suppression efficiencies in EP than APP. An EP blend containing 15 wt% DDP displays a limiting oxygen index (LOI) value of 37.1% and a UL 94 V-0 rating, and further exhibits a 32.3% reduction in total heat release and a 48.0% reduction in total smoke production compared with pure EP. The presence of DDP greatly facilitates char formation during combustion, and the char mass from thermal decomposition of an EP blend is 37.8% smaller than that of an EP blend containing 15 wt% DDP at 800 °C. The incorporation of DDP into EP blends has a smaller impact on the glass transition temperature and tensile strength than those of a comparable level of APP. This reflects the better compatibility of DDP with the EP matrix compared with that for APP. [ABSTRACT FROM AUTHOR]