Functionalized graphene with Co-ZIF adsorbed borate ions as an effective flame retardant and smoke suppression agent for epoxy resin

In order to reduce the fire risk of epoxy resin (EP), functionalized reduced graphene oxide (RGO) with Co-ZIF (zeolitic imidazolate frameworks-67) adsorbed borate ions (ZIF-67/RGO-B) was prepared. The results of transmission electron microscopy (TEM) showed that ZIF-67 was grown on the surface of RGO triumphantly. In addition, the structure of ZIF-67/RGO-B was not significantly changed compared with ZIF-67/RGO. Subsequently, ZIF-67/RGO-B was added into EP by a simple blending method. The combustion results showed that the heat and smoke production of EP composites were obviously reduced. In particular, compared with pure EP, the peak heat release rate (pHRR), the total heat release (THR) and the maximum value of smoke density (D-s,D-max) of the composite with 2 wt% ZIF-67/RGO-B were reduced by 65.1%, 41.1% and 66.0%, respectively. The main mechanism of ZIF-67/RGO-B for reducing the fire risk of EP was analyzed according to the results of the char analysis. This work provided a new type of modified RGO for reducing the fire hazard of EP.