Synthesis of phosphorus-containing benzimidazole-based copper complex and properties of flame-retardant epoxy resin

Abstract

Abstract: In order to modify the flame retardant property of epoxy resin, a new type of phosphorous/nitrogen dihydric compound, phosphoric acid 4-(1H-benzoimidazol-2-yl)-phenyl ester diphenyl ester (PBIm), was prepared by substitution reaction and condensation reaction, and used as an organic functional group to react with copper acetate-hydrate to synthesize phosphorus-containing benzimidazole-based copper complex flame retardant PBIm-Cu. It was added to epoxy resin (EP) to prepare flame retardant epoxy resin composite (PBIm-Cu /EP). The structure of the flame retardants PBIm and PBIm-Cu was characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, hydrogen nuclear magnetic spectrum and phosphorus nuclear magnetic spectrum. Thermogravimetric analyzer (TGA), limiting oxygen index (LOI) and cone calorimeter (CCA) were used to test the thermal stability and flame retardancy of composite materials. The PBIm-Cu/EP system with a PBIm-Cu mass fraction of 7% passed the V-1 level in the vertical combustion test, and the LOI was increased to 31.6%. Moreover, compared with pure EP, the peak heat release rate (PHRR), total heat release rate (THR) and total smoke exhaust rate (TSP) were decreased by 64%, 41% and 43%, respectively, and the residual weight rate reached 26.7%. SEM results show that the surface of the carbon layer after the combustion of PBIm-Cu/EP material is smooth, continuous and dense.

Key words: flame retardant, organometallic complex, epoxy resin, flame retardant properties

CLC Number:

O633.13

YANG Bao-ping, CHEN Xiao-dong, WANG Nian-nian, CUI Jin-feng, GUO Jun-hong. Synthesis of phosphorus-containing benzimidazole-based copper complex and properties of flame-retardant epoxy resin[J]. Journal of Lanzhou University of Technology, 2021, 47(6): 66-73.

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