ZIF-8@Co-doped boronate ester polymer core-shell particles: Catalytically enhancing the nonflammability and smoke suppression of epoxy resin

Starting from a typical metal-organic framework (MOF) ZIF-8, a core-shell flame retardant named ZIF-8@BP-Co was synthesized by using ZIF-8 as the core and boronate ester polymer (BP) doped with Co 2+ as the shell. The thermal stability and possible thermal degradation pathways of ZIF-8@BP-Co were characterized by TG and Py-GC/MS. ZIF-8@BP-Co was introduced into epoxy resin (EP) to reduce the flammability and smoke toxicity of EP nanocomposites. At the same time, the EP/ZIF-8@BP-Co achieved a V-0 rating in the UL-94 test, and its mechanical properties were also enhanced. Compared with EP, the peak heat release rate (pHRR), total heat release (THR), peak of smoke production rate (pSPR) and total smoke production (TSP) of EP/ZIF-8@BP-Co decrease by 51.3%, 13.2%, 37.2% and 20.9%, respectively. This work may be of interest in the design of multi-element flame retardant particles, especially in improving the compatibility between MOFs and polymer matrix.