The effects of DOPO modified Co-based metalorganic framework on flame retardancy, stiffness and thermal stability of epoxy resin
Liyun Cai, Fei Xin, Congcong Zhai, Yu Chen, Bo Xu, Xiangmei Li
Abstract
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. Then DOPO@ZIF-67 was synthesized by modifying ZIF-67 with 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 that DOPO@ZIF-67 formed a more continuous and dense microstructure, which can enhance the thermal barrier and the physical barrier effect. The addition of DOPO@ZIF-67 also can effectively improve the stiffness and damping coefficient of EP composite material. The porous skeleton structure of DOPO@ZIF-67 can endow EP with rigidity and flame-retardant properties. Furthermore, the existence of DOPO made the combination of ZIF-67 with EP better. The results of this study suggest that DOPO@ZIF-67 may be a good additive for modification of the properties of epoxy thermosetting materials.