Facile fabrication of multifunctional flame retardant epoxy resin by a core–shell structural AgNC@boronate polymer

Multifunctional flame retardant epoxy resin (EP) have a huge impact in electrical &electronics, big data, internet of things, artificial intelligence and 5G fields, while their manufacturing faces significant challenges. Herein, a kind of boronate polymer with P, B and N elements, which has good compatibility with epoxy resin, was coated on the surface of silver nanocube (AgNC) to prepare multifunctional nanoparticles (AgNC@BP). Then, a multifunctional EP nanocomposite with good flame retardancy, mechanical properties, thermal conductivity and electromagnetic wave absorption properties was prepared by using AgNC@BP as filler. As expected, AgNC@BP significantly improved the above-mentioned properties of EP nanocomposite. First, the bending strength and thermal conductivity (TC) of EP/AgNC@BP5 nanocomposite were demonstrated to have an increase of 12.9% and 36.0%, respectively. Synchronously, at a relatively low AgNC@BP content (5 wt%), the nanocomposite achieved a reflection loss (RL) of −18.81 dB at 2 mm thickness, which indicated that it has electromagnetic wave (EMW) absorption properties. Besides, 5 wt% addition of AgNC@BP endowed EP/AgNC@BP5 nanocomposite with excellent flame retardancy and low heat release during combustion compared to pure EP. That is, the UL-94 grade of the nanocomposite reached to V-0, LOI increased to 29.5% and the peak heat release rate (pHRR) was reduced by 39.0% compared to pure EP. All in all, this work provides a strategy for the design of multifunctional EP.