Abstract: A copper-based metal-organic framework(Cu-MOF) with the reactive organic ligand 4,4'-{[(1E,1'E)-1,4-phenylene]bis(methylene)}bis(azanediyl)dibenzoic acid(TBPA) was first synthesized via ultrasound-assisted and hydrothermal methods. Then, a flame-retardant Cu-MOF derivative(Cu-MOF@DOPO) was prepared by reacting Cu-MOF with a reactive flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO). The Cu-MOF@DOPO was confirmed by multiple characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy(TEM), and X-ray diffraction(XRD). The effect of Cu-MOF@DOPO on flame retardant, mechanical and thermal properties of epoxy resin(EP) was investigated. The results indicated that EP containing 2 wt% Cu-MOF@DOPO(EP/2MD) had a limiting oxygen index(LOI) of 29.6% and achieved a UL-94 V-0 rating. Meanwhile, the peak heat release rate(pHRR) and total heat release(THR) of EP/2MD decreased by 14.2% and 8.1%, respectively, while the total smoke production(TSP) slightly deceased compared with those of pure EP. During combustion, Cu-MOF@DOPO in EP exerted its flame-retardant action both in the condensed phase and the gas phase. Compared with EP composites filled with Cu-MOF or the flame-retardant ligand TBPA-DOPO, the EP/Cu-MOF@DOPO composites exhibited a higher glass transition temperature and enhanced mechanical properties.

Key words: Epoxy resin, Flame-retardant metal-organic framework, Flame retardancy, Mechanical property, Thermal property