The effects of DOPO modified Co-based metalorganic framework on flame retardancy, stiffness and thermal stability of epoxy resin

In this work, the effect of a modified metal organic framework material on the fire resistance and mechanical properties of epoxy resin (EP) has been explored. The cobalt based metal organic framework (ZIF-67) was synthesized from an organic ligand with a Schiff base structure. ThenDOPO@ZIF-67was synthesized by modifyingZIF-67with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and its effect on EP modification was explored. Compared with the pure EP, 4%DOPO@ZIF-67/EP passed the UL94 V-0 level and the ultimate oxygen index (LOI) reached 32.1%. The SEM pictures of carbon residue indicated thatDOPO@ZIF-67formed a more continuous and dense microstructure, which can enhance the thermal barrier and the physical barrier effect. The addition ofDOPO@ZIF-67also can effectively improve the stiffness and damping coefficient of EP composite material. The porous skeleton structure ofDOPO@ZIF-67can endow EP with rigidity and flame-retardant properties. Furthermore, the existence ofDOPOmade the combination ofZIF-67with EP better. The results of this study suggest thatDOPO@ZIF-67may be a good additive for modification of the properties of epoxy thermosetting materials.