Enhancing flame retardance of epoxy resin by incorporation into ammonium polyphosphate/boron nitride nanosheets/zinc ferrite three‐dimensional porous aerogel via vacuum‐assisted infiltration

Abstract

ABSTRACTBoron nitride nanosheets (BNNSs) were combined with ammonium polyphosphate (APP) and zinc ferrite (ZF) nanoparticle to prepare APP/BNNS/ZF composite aerogels via a freeze‐drying method. Then, epoxy resin (EP) was incorporated into the pores of the as‐obtained aerogels via a vacuum‐assisted infiltration method to afford APP/BNNS/ZF‐EP composites with greatly improved fire resistance. The flame‐retardant performance of the as‐prepared composites was evaluated by cone calorimetry test; and the flame‐retardant mechanism of the aerogels was discussed in relation to thermogravimetric‐infrared analysis of the pyrolysis products. Findings demonstrate that the APP/BNNS/ZF‐EP composite containing 24.0 wt % of the APP/BNNS/ZF aerogel exhibits superior flame‐retardant performance; and its peak heat release rate and total heat release are reduced by 86.2 and 86.5% as compared with those of pristine EP. The reason lies in that APP can be decomposed in the early stage of burning to generate phosphoric acid, thereby promoting the formation of char layer; ZF can catalyze the charring process; and BNNS can act as the physical barrier to retard the burning of EP. In addition, the APP10/BNNS1/ZF0.1‐EP composite can be endowed with superhydrophobicity via the modification of polydimethylsiloxane and hydrophobic nanosilica, which could contribute to broadening its scope of application. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48609.Highlights Flame‐retardant APP/BNNS/ZF aerogels were prepared by a freeze‐drying method. APP/BNNS/ZF‐EP composites were obtained via a vacuum‐assisted infiltration method. The pHRR of composites are reduced by 86.2% as compared with that of pristine EP. The EP composites exhibit excellent flame retardancy and superhydrophobicity.